Accessory, image pickup apparatus on which same is mountable, and camera system

ABSTRACT

An interchangeable lens assembly includes a plurality of lens-side claw portions and a lock pin concave portion. Furthermore, internal angles of a quadrangle formed by connecting a center of a first lens-side claw portion, a center of a second lens-side claw portion, a center of a third lens-side claw portion, and a center of the lock pin concave portion satisfies a predetermined condition.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to an accessory, an image pickupapparatus on which the accessory is mountable, and a camera system.

Description of the Related Art

U.S. Pat. No. 8,430,582 discloses a camera body (an image pickupapparatus), and an interchangeable lens assembly (an interchangeablelens) as a camera accessory (an optical apparatus) that can bedetachably mounted to the camera body. In U.S. Pat. No. 8,430,582, oninitially inserting the interchangeable lens assembly into the camerabody, the interchangeable lens assembly is said to be in aninsertion/removal phase in which it is rotatable in an, so-called,attaching direction, wherein it becomes removably attached to the camerabody. In other words, during the above operation, the interchangeablelens assembly is transitioned to a mounted phase (position), bayonetclaw portions on the interchangeable lens assembly side and bayonet clawportions on the camera body side are coupled to each other, and mountingof the interchangeable lens assembly on the camera body is completed.

In U.S. Pat. No. 8,430,582, a lock pin that can be advanced andretracted in an optical axis direction of the interchangeable lensassembly is provided on the camera body side, and a lock pin grooveportion, in which the lock pin is insertable is provided on theinterchangeable lens assembly side. In U.S. Pat. No. 8,430,582, byinserting the lock pin to the lock pin groove portion, theinterchangeable lens assembly is secured to the camera body. Theinterchangeable lens assembly can only be removed from the camera bodyby retracting the lock pin from the lock pin groove portion.

The interchangeable lens assembly is required to be mountable to thecamera body, when attached, in a stable manner even in a case in whichexternal force such as a vibration is applied to the interchangeablelens assembly. However, in the interchangeable lens assembly describedin U.S. Pat. No. 8,430,582, among three bayonet claw portions, thedispositional relationship between one of the two bayonet claw portionsthat are near the lock pin groove portion in which the lock pin isinserted and the lock pin groove portion, and the dispositionalrelationship between the other one of the two bayonet claw portions andthe lock pin groove portion differ greatly. Accordingly, there is aconcern that in U.S. Pat. No. 8,430,582, it is difficult to keep theinterchangeable lens assembly mounted on the camera body, in a stablemanner, when external forces from various directions is applied or whenthe orientation of the interchangeable lens assembly is changed.

SUMMARY OF THE INVENTION

Accordingly, the present disclosure provides an accessory that iscapable of being mounted on an image pickup apparatus in a more stablemanner, an image pickup apparatus on which the accessory can be mounted,and a camera system.

An accessory of the present disclosure is an accessory configured to bedetachably mountable to an image pickup apparatus that includes a firstmount portion and a pin, the first mount portion including a pluralityof first bayonet claw portions, the accessory including a second mountportion that includes a plurality of second bayonet claw portionsconfigured to enable engagement with the plurality of first bayonet clawportions, and a concave portion in which the pin is inserted when theaccessory is mounted to the image pickup apparatus, in which when viewedin a central axis direction of the second mount portion, a concaveportion side is a side on which the concave portion is provided withrespect to a boundary line, the boundary line being a line that isorthogonal to a line passing through a center of the concave portion anda central axis of the second mount portion and that passes through thecentral axis of the second mount portion, among the plurality of secondbayonet claw portions, two second bayonet claw portions that have atleast a portion disposed on the concave portion side are denoted as afirst concave portion side bayonet claw portion and a second concaveportion side bayonet claw portion, the plurality of second bayonet clawportions include the first concave portion side bayonet claw portion,the second concave portion side bayonet claw portion, and an oppositeside bayonet claw portion in which both ends thereof are provided onopposite side of the concave portion side with respect to the boundaryline,

θ10+θ20+θ30+θL=360°, and

75°≤θ10≤105°,75°≤θ20≤105°,75°≤θ30≤105°, and 75°≤θL≤105°

are satisfied, where, among internal angles of a quadrangle formed byconnecting a center of the opposite side bayonet claw portion, a centerof the second concave portion side bayonet claw portion, a center of thefirst concave portion side bayonet claw portion, and the center of theconcave portion, θ10 is an angle of a first internal angle in which avertex thereof is the center of the opposite side bayonet claw portion,θ20 is an angle of a second internal angle in which a vertex thereof isthe center of the second concave portion side bayonet claw portion, θ30is an angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings. Each of the embodiments of the present inventiondescribed below can be implemented solely or as a combination of aplurality of the embodiments. Also, features from different embodimentscan be combined where necessary or where the combination of elements orfeatures from individual embodiments in a single embodiment isbeneficial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a camera body and an interchangeable lensassembly according to an exemplary embodiment of the present disclosure.

FIG. 2 is an exploded perspective view of mount portions of theexemplary embodiment of the present disclosure.

FIG. 3A is a diagram of a lens mount in a normal position viewed from animage pickup plane side, and FIG. 3B is a cross sectional view of a lensmount.

FIG. 4A is a diagram of a camera mount in a normal position viewed froman image pickup plane side, and FIG. 4B is a cross sectional view of acamera mount.

FIG. 5 is a diagram illustrating an insertion/removal state of the lensmount and the camera mount in a normal position viewed from an imagepickup plane side.

FIG. 6 is a diagram illustrating a mounted state of the lens mount andthe camera mount in a normal position viewed from an image pickup planeside.

FIG. 7 is an explanatory drawing of a polygonal shape formed of a centerof a lock pin groove, and centers of lens-side claw portions.

FIGS. 8A and 8B are explanatory drawings of the center of a lock pingroove and a center of lens-side claw portion.

FIG. 9A is a block diagram of a camera and an interchangeable lensassembly according to the exemplary embodiment, and FIG. 9B is a blockdiagram of terminals of the camera and the interchangeable lens assemblyaccording to the exemplary embodiment.

FIG. 10 is an exploded perspective view of a mount mechanism accordingto a modification.

FIGS. 11A to 11C are drawings illustrating a mount mechanism accordingto the modification in a non-connected state.

FIGS. 12A to 12C are drawings illustrating a mount mechanism accordingto the modification in a connected state.

FIG. 13A is a detailed diagram illustrating a dispositional relationshipof a camera contact pin according to the present exemplary embodiment,FIG. 13B is a perspective view illustrating a dispositional relationshipof a camera contact pin according to the present exemplary embodiment.

FIG. 14A is a detailed diagram illustrating a dispositional relationshipof lens contact portions according to the present exemplary embodiment,FIG. 14B is a perspective view illustrating a dispositional relationshipof the lens contact portions according to the present exemplaryembodiment.

FIG. 15A is a diagram illustrating an insertion phase state when theinterchangeable lens assembly is attached to the camera according to thepresent exemplary embodiment viewed from the camera photographer side,and FIG. 15B is a diagram illustrating a lock phase state when theinterchangeable lens assembly is attached to the camera according to thepresent exemplary embodiment viewed from the camera photographer side.

FIGS. 16A and 16B are diagrams describing a first conversion adapterthat is mountable to the camera body, and a second interchangeable lensassembly.

FIGS. 17A and 17B are diagrams describing a second conversion adapterthat is mountable to a camera body, and the first interchangeable lensassembly.

FIGS. 18A through 18C is a diagram for exemplarily describing angle sodisposing bayonet claw portions in a camera mount provided on one end ofthe first conversion adapter.

FIGS. 19A and 19B are diagrams exemplarily describing angle so disposingbayonet claw portions in the lens mount provided on the other end of thefirst conversion adapter.

FIGS. 20A and 20B are diagrams exemplarily describing a mounting methodof a predetermined imaging apparatus and a predetermined interchangeablelens assembly having claw portions and recesses that interfere with eachother.

FIGS. 21A and 21B are diagrams exemplarily describing the way in whichclaw portions interfere with each other when attempting to mount thelens mount side to the camera mount side according to an embodiment ofthe present invention.

FIGS. 22A through 22D is a diagram exemplarily describing a case ofattempting to insert incompatible claw portions into recesses at thelens mount side and camera mount side according to an embodiment of thepresent invention.

FIGS. 23A and 23B are diagrams exemplarily describing angle so disposingbayonet claw portions in the camera mount provided on one end of thesecond conversion adapter.

FIGS. 24A through 24C are diagrams exemplarily describing angle sodisposing bayonet claw portions in a lens mount provided on the otherend of the second conversion adapter.

FIGS. 25A and 25B are diagrams exemplarily describing the way in whichclaw portions interfere with each other, when attempting to mount areference claw at the lens mount side to a reference recess at thecamera mount side according to an embodiment of the present invention.

FIGS. 26A through 26D are diagrams exemplarily describing the way inwhich claw portions interfere with each other, when attempting to mounta claw other than the reference claw at the lens mount side to areference recess at the camera mount side according to an embodiment ofthe present invention.

FIG. 27 is a diagram exemplarily describing a state in which clawportions provided to the camera mount side and lens mount side accordingto an embodiment of the present invention are engaged.

DESCRIPTION OF THE EMBODIMENTS Block Configuration of InterchangeableLens Assembly and Camera Body

Referring first to FIG. 1, a block configuration of an interchangeablelens assembly 100 and a camera body 200 according to the presentexemplary embodiment will be described. FIG. 1 is a block diagram of acamera system 300 including the interchangeable lens assembly (anoptical apparatus, an accessory, a lens apparatus) 100 and the camerabody 200. In FIG. 1 and the diagrams described hereinafter, unnecessarycomponents, components related to the design, and the like are omitted.The interchangeable lens assembly 100 can be mounted and dismounted fromthe camera body 200.

The camera body 200 includes an image pickup member 202 that is aphotoelectric conversion element or an image pickup element thatincludes a CCD and a CMOS and that converts optical information of asubject obtained through the interchangeable lens assembly 100 into anelectric signal, that is, the image pickup member 202 performsphotoelectric conversion of the image of the subject. The camera body200 further includes a camera mount (a first mount portion) 201connected to a lens mount (a second mount portion) 101 on aninterchangeable lens assembly 100 side, and a camera housing 205 thatholds the image pickup member 202 and the like.

Other than the image pickup member 202 and the camera mount 201, thecamera body 200 also includes a camera communication member thatcommunicates with a lens communication member on the interchangeablelens assembly 100 side, a photometry member that performs photometry, arangefinder that performs ranging, a recording device that records dataof a photograph and a moving image that have been taken. The camera body200 further includes a setting member that sets photographingconditions, such as a shutter speed, a release member that the user canoperate, a display member that displays various pieces of information tothe user, and a power source. Moreover, the camera body 200 furtherincludes a camera CPU that is a control member that controls the imagepickup member 202 and the like.

The interchangeable lens assembly 100 includes a lens barrel 104, andthe lens mount (a camera accessory mount) 101. An electric communicationbetween the interchangeable lens assembly 100 and the camera body 200 isperformed by the lens communication member and the camera communicationmember that include a plurality of electrical contacts capable of beingelectrically connected to the counterpart. Various types of information,such as power supplying information and control information, can beexchanged between the camera CPU and a lens CPU.

Other than the lens mount 101, the interchangeable lens assembly 100includes a zooming lens unit ZLU that moves when zooming, a focusinglens unit FLU that moves when focusing, and a shift lens unit SLU thatmoves to perform a camera shake correction. The interchangeable lensassembly 100 further includes a lens unit LU other than the zooming lensunit ZLU, the focusing lens unit FLU, and the shift lens unit SLU, anaperture unit DU, and a ND filter NDF.

The interchangeable lens assembly 100 further includes a zoom drivingmember that drives the zooming lens unit ZLU, a focus driving memberthat drives the focusing lens unit FLU, and an aperture driving memberthat drives the aperture unit DU. The interchangeable lens assembly 100further includes an ND driving member that drives the ND filter NDF, andan image stabilization driving member that drives the shift lens unitSLU. The interchangeable lens assembly 100 further includes the lenscommunication member, and the lens CPU that serves as a control memberthat controls the lens communication member and the driving membersdescribed above.

Configuration of Lens-Side Mount Portion and Camera-Side Mount Portion

Referring next to FIG. 2, the mount portions of the interchangeable lensassembly 100 and the camera body 200 will be described. FIG. 2 is anexploded perspective view of the mount portions of the interchangeablelens assembly 100 and the camera body 200.

An optical axis O is an axis that indicates a center of a light fluxthat is guided by the interchangeable lens assembly 100 and that is fromthe subject ideally facing the interchangeable lens assembly 100. A lockpin (a pin) 203 is an abutting pin (a restricting portion, a convexportion) that, in a state in which the lens mount 101 and the cameramount 201 are in a mounted state, restricts the cancellation of themounted state. The lock pin 203 is capable of advancing and retreatingin a direction parallel to the optical axis O and has a biasingstructure that applies biasing force in the advancing direction at alltimes.

When the interchangeable lens assembly 100 is in an insertion/removalstate with respect to the camera body 200, the lock pin 203 beingabutted against the lens mount 101 is pushed into a retreated position.In the above state, the lens mount 101 and the camera mount 201 are incontact with each other. In the mounted state, the lock pin 203 enters(is inserted in) a lock pin groove portion (an inserted portion, agroove portion, a concave portion, a recess) 102 of the lens mount 101,and cancellation of the mounted state is restricted by the lock pin 203and the lock pin groove portion 102.

When cancelling the mounted state, to remove the interchangeable lensassembly, a release operation member 204 is pushed in, the lock pin 203is moved from an advanced position to a retreated position, and theinterchangeable lens assembly 100 is rotated to an unlocking position.While in a state (the insertion/removal state) in which the contactsurfaces of the lens mount 101 and the camera mount 201 are in contactwith each other, by relatively moving the interchangeable lens assembly100 and the camera body 200 from the unlocking position to a lockingposition, the interchangeable lens assembly 100 and the camera body 200are connected to each other, or the interchangeable lens assembly 100and the camera body 200 are brought to the mounted state.

As described above, the camera housing 205 is a base material that holdsportions of the camera body 200. More specifically, referring to FIG. 2,the camera housing 205 holds the camera mount 201, a holding member ofthe camera-side electrical contacts (camera-side terminals or firstterminals) that are communication members, camera mount fixing members206, and a lens mount biasing member 207. The lens mount biasing member207 is a biasing member that pulls in lens claw portions provided in thelens mount 101 described later towards a camera mount 201 side and isinterposed in a space between the camera mount 201 and the camerahousing 205.

The lens mount 101 is fixed to the lens barrel (an accessory main body)104 with lens mount fixing members (mount fixing members) 103. A lenscontact portions (lens-side terminals or second terminals) holdingmember 105 is a holding member that holds a plurality of electricalcontacts (terminals) provided on the interchangeable lens assembly 100side, and is fixed to the lens mount 101 with a lens contact portionsholding member fixing member 106.

Disposition of Bayonet Claw Portions of Lens-Side Mount

Referring next to FIG. 3, a phase (disposition) of lens-side bayonetclaw portions of the lens mount 101 will be described. Note that in thepresent exemplary embodiment, the bayonet claw portions on the lens-sideis referred to as lens-side claw portions, and the bayonet claw portionson the camera-side is referred to as camera-side claw portions.

FIG. 3 is a diagram viewing the lens mount 101 from an image pickupplane side when the lock pin groove portion 102 in the mounted state,which is a state in which the lock pin 203 is engaged with the lock pingroove portion 102, is at a position (hereinafter, referred to as anormal position) that is a position on the left side when viewed fromthe image pickup plane side. Note that in the present exemplaryembodiment, the lens side is a paraphrase of an optical apparatus(accessory) side, and the camera side is a paraphrase of an image pickupapparatus side.

As illustrated in FIG. 3, when viewed in the optical axis O direction,the lens mount 101 includes a first lens-side claw portion 107 a, asecond lens-side claw portion 107 b, and a third lens-side claw portion107 c that have dimensions in a radial direction and a circumferentialdirection of an opening included in the lens mount 101. The firstlens-side claw portion 107 a, the second lens-side claw portion 107 b,and the third lens-side claw portion 107 c are included in theinterchangeable lens assembly 100, and are a plurality of lens-side clawportions (a plurality of second engagement portions or a plurality ofsecond bayonet claw portions) that are capable of engaging with aplurality of camera-side claw portions (a plurality of first engagementportions or a plurality of first bayonet claw portions). Furthermore,the lens mount 101 includes a lens-side diameter fitting portion 109that becomes a restriction in a direction orthogonal to the optical axiswhen the lens mount 101 is attached to the camera mount 201.

Note that in the description hereinafter, a portion between the thirdlens-side claw portion 107 c and the first lens-side claw portion 107 ais referred to as a first lens-side cutaway (a first cutaway, a firstconcave portion, a first recess, the same applies hereafter) 108 a, anda portion between the first lens-side claw portion 107 a and the secondlens-side claw portion 107 b is referred to as a second lens-sidecutaway (a second cutaway) 108 b. Furthermore, a portion between thesecond lens-side claw portion 107 b and the third lens-side claw portion107 c is referred to as a third lens-side cutaway (a third cutaway) 108c. Furthermore, one end of the first lens-side claw portion 107 a isreferred to as a first lens-side end 107 a 1 and the other end isreferred to as a second lens-side end 107 a 2. Furthermore, lens-sideends of the lens-side claw portions in the clockwise direction in FIG. 3from the second lens-side end 107 a 2 are referred to as a thirdlens-side end 107 b 1, a fourth lens-side end 107 b 2, a fifth lens-sideend 107 c 1, and a sixth lens-side end 107 c 2.

As illustrated in FIG. 3, in the present exemplary embodiment, when inthe mounted state and when at a normal position, which is a position inwhich the lock pin 203 is positioned on the left side when viewed from aphotographer side, the first lens-side claw portion 107 a is disposedopposite to the lock pin 203 with the optical axis O in between.Furthermore, the second lens-side claw portion 107 b and the thirdlens-side claw portion 107 c are sequentially disposed in the clockwisedirection from the first lens-side claw portion 107 a.

Configuration to Mount Interchangeable Lens Assembly 100 on Camera Body200 in Further Stable Manner

Dispositions of the lens-side claw portions to mount the interchangeablelens assembly 100 on the camera body 200 in a further stable manner willbe described. Lines and angles needed to describe the dispositions ofthe lens-side claw portions will be defined first.

A line passing the center of the lock pin groove portion 102 and acentral axis of the interchangeable lens assembly 100, in other words,the optical axis O, when viewed in a central axis direction of theinterchangeable lens assembly 100 (when viewed in a central axisdirection of the lens mount 101), in other words, when viewed in anoptical axis direction of the interchangeable lens assembly 100 isreferred to as line L1 (a reference line). Note that line L1 may be aline that passes the center of the lock pin 203 and the optical axis O.The central axis of the interchangeable lens assembly 100 or a centralaxis of the lens mount 101 may be a central axis of the opening of thelens mount 101.

A line that is orthogonal to line L1 and that passes the optical axis Ois referred to as line L2. Furthermore, a side on which the lock pingroove portion 102 is provided with respect to line L2 serving as aboundary line, in other words, the left side of line L2 in FIG. 3 isreferred to a lock pin groove portion side (an inserted portion side ora groove portion side).

Furthermore, among the lens-side claw portions, the lens-side clawportions that each have at least a portion thereof disposed on the lockpin groove portion side are referred to as a first inserted-portion-sideengagement portion (a first recess-side bayonet claw portion, a firstgroove portion side bayonet claw portion, a first concave portion sidebayonet claw portion) and a second inserted-portion-side engagementportion (a second recess-side bayonet claw portion, a second grooveportion side bayonet claw portion, a second concave portion side bayonetclaw portion). Referring to FIG. 3, the first inserted-portion-sideengagement portion is the third lens-side claw portion 107 c, and thesecond inserted-portion-side engagement portion is the second lens-sideclaw portion 107 b.

An angle formed between line L3 that passes the fifth lens-side end 107c 1, which is a lens-side end of the first inserted-portion-sideengagement portion on the lock pin groove portion 102 side, and theoptical axis O and line L1 is assumed to be θ1. An angle formed betweenline L4 that passes the fourth lens-side end 107 b 2, which is alens-side end of the second inserted-portion-side engagement portion onthe lock pin groove portion 102 side, and the optical axis O and line L1is assumed to be θ2.

The interchangeable lens assembly 100 satisfies

0.65≤θ1/θ2≤1.35.  (1)

In the present exemplary embodiment, θ1=54° and θ2=42°, and θ1/θ2=1.29;accordingly, conditional expression (1) is satisfied. In the presentexemplary embodiment, θ1 is larger than θ2. In such a case, conditionalexpression (1) becomes 1.00<θ1/θ2≤1.35. Note that the values θ1 and θ2may be the same and, in such a case, the value of conditional expression(1) becomes 1.00. In other words, in a case in which θ1≥θ2, conditionalexpression (1) becomes 1.00≤θ1/θ2≤1.35.Note that interchangeable lens assembly 100, more preferably, satisfies

0.70≤θ1/θ2≤1.30.  (1a)

Note that the lower limit of conditional expression (1a) may be 0.80 or0.90. Moreover, conditional expression (1) may be 0.60≤θ1/θ2≤1.40.

As illustrated in FIG. 3, when the accessory is at the normal position,the angle θ2 on a gravity direction side with respect to the referenceline L1 is smaller than angle θ1 on a side opposite to the gravitydirection side with respect to the reference line L1. In other words,when the accessory is at the normal position, the second groove portionside bayonet claw portion is positioned on the gravity direction sidewith respect to the first groove portion side bayonet claw portion. Byhaving the magnitudes of θ1 and θ2 be in such a relationship, a frontend of the interchangeable lens assembly 100 at the normal position canbe prevented from tilting in the gravity direction.

In other words, in the interchangeable lens assembly 100 the secondlens-side claw portion 107 b and the third lens-side claw portion 107 care disposed in a substantially uniform manner when viewed from the lockpin groove portion 102. In other words, in the interchangeable lensassembly 100, the lock pin groove portion 102 is provided in a vicinityof a middle of a region between the second lens-side claw portion 107 band the third lens-side claw portion 107 c. By having theinterchangeable lens assembly 100 have the above-describedconfiguration, the interchangeable lens assembly 100 can be mounted onthe camera body 200 in a more stable manner.

The lock pin 203 and the lock pin groove portion 102, the secondlens-side claw portion 107 b, and the third lens-side claw portion 107 cthat fix the position of the interchangeable lens assembly 100 when theinterchangeable lens assembly 100 is mounted on the camera body 200 aredisposed in a well-balanced manner. Accordingly, the interchangeablelens assembly 100 can be mounted on the camera body 200 in a more stablemanner even when external force from various directions are applied tothe interchangeable lens assembly 100 or when the orientation of theinterchangeable lens assembly 100 is changed.

Furthermore, more preferably, the interchangeable lens assembly 100further satisfies the following condition. It is more preferable that,in addition to the first inserted-portion-side engagement portion andthe second inserted-portion-side engagement portion described above, theplurality of lens-side claw portions include an opposite-side engagementportion described next. The opposite-side engagement portion is alens-side claw portion in which both lens-side ends thereof are providedon the side opposite to the lock pin groove portion side with respect toline L2 that is a boundary line, in other words, the opposite-sideengagement portion is a lens-side claw portion in which both lens-sideends thereof are provided on the right side of line L2 in FIG. 3. In thepresent exemplary embodiment, the first lens-side claw portion 107 a isthe opposite-side engagement portion. As illustrated in FIG. 3, bothends of the opposite-side engagement portion are positioned on the rightside of line L2.

Furthermore, line L1 and the opposite-side engagement portion overlapeach other. In addition to the configuration described above in whichthe lock pin groove portion 102 is provided in the vicinity of themiddle of the region between the second lens-side claw portion 107 b andthe third lens-side claw portion 107 c, by having the opposite-sideengagement portion at the position described above, the following effectcan be obtained. In other words, in the present exemplary embodiment,when the interchangeable lens assembly 100 is mounted on the camera body200, the lock pin 203 and the lock pin groove portion 102, and eachlens-side claw portion that fix the position of the interchangeable lensassembly 100 are disposed uniformly at intervals of substantially 90°.Accordingly, the interchangeable lens assembly 100 can be mounted on thecamera body 200 in a more stable manner.

Furthermore, an angle formed between line L5 that passes the firstlens-side end 107 a 1 that is a lens-side end of the first lens-sideclaw portion 107 a, which is the opposite-side engagement portiondescribed above, on the third lens-side claw portion 107 c side and theoptical axis O, and line L1 is assumed to be θ3. Furthermore, an angleformed between line L6 that passes the second lens-side end 107 a 2 thatis a lens-side end of the first lens-side claw portion 107 a on thesecond lens-side claw portion 107 b side and the optical axis O, andline L1 is assumed to be θ4. The interchangeable lens assembly 100preferably satisfies

0.60≤θ3/θ4≤0.90,  (2)

or

0.60≤θ3/θ4≤0.80.  (2a)

In other words, when the first lens-side claw portion 107 a is dividedin the up-down direction in FIG. 3 with line L1, the portion on thelower side is preferably slightly longer than the portion on the upperside. Note that the upper limit of conditional expression (2a) may be0.70. In the present exemplary embodiment, since θ3=21°, θ4=32°,θ3/θ4=0.66, conditional expression (2) is satisfied. In the presentexemplary embodiment, θ4 is larger than θ3.

When θ3/θ4 deviates from the upper limit of conditional expression (2),the portion on the lower side of the first lens-side claw portion 107 athat is divided by line L1 is, with respect to line L1, in other words,with respect to the lock pin groove portion 102, excessively long withrespect to the portion on the upper side. In such a state, the length ofthe second lens-side cutaway 108 b needs to be reduced, and a length ofa second camera-side claw portion 208 b described later needs to bereduced accordingly. As a result, the area of the region in which thelens-side claw portion and the camera-side claw portion engage with eachother becomes smaller, and it may not be possible to mount theinterchangeable lens assembly 100 on the camera body 200 in a stablemanner.

When θ3/θ4 deviates from the lower limit of conditional expression (2),the effect described next resulting from the portion on the lower sideof the first lens-side claw portion 107 a that is divided by line L1being longer than the portion on the upper side may not be sufficientlyobtained.

Generally, in many cases, imaging is performed using the camera system300 while the lock pin groove portion 102 is at the normal position,that is, on the left side when viewed from an image pickup member 202side. When the camera system 300 is at the normal position, the downwarddirection in the sheet surface of FIG. 3 is the gravity direction.Accordingly, in order to prevent the interchangeable lens assembly 100at the normal position from tilting, with respect to the camera body200, in a direction approaching the ground surface by its own weight, itis preferable that the portion on the lower side of the first lens-sideclaw portion 107 a that is divided by line L1 is longer than the portionon the upper side.

Furthermore, as illustrated in FIG. 3, both the third lens-side clawportion 107 c that is the first inserted-portion-side engagement portionand the second lens-side claw portion 107 b that is the secondinserted-portion-side engagement portion overlap line L2 that is theboundary line described above. With the above configuration, a change inthe orientation in which the interchangeable lens assembly 100 tilts canbe suppressed.

Furthermore, more preferably, the interchangeable lens assembly 100further satisfies the following condition. In other words, theinterchangeable lens assembly 100 satisfies

90°<θ1+θ2<180°.  (3)

The configuration satisfying conditional expression (3) is significantof the angle between the second lens-side claw portion 107 b and thethird lens-side claw portion 107 c being an obtuse angle. As describedabove, in the present exemplary embodiment, θ1=54°, θ2=42°, andθ1+θ2=96° are satisfied. The upper limit of conditional expression (3)may be 120° or 100°.

The angle between the second lens-side claw portion 107 b and the thirdlens-side claw portion 107 c being an obtuse angle is significant of thesecond lens-side claw portion 107 b and the third lens-side claw portion107 c being apart from each other to some extent. As illustrated in FIG.3, the lock pin groove portion 102 is provided between the secondlens-side claw portion 107 b and the third lens-side claw portion 107 c.

In the present exemplary embodiment, the lock pin groove portion 102 isprovided in a region between the second lens-side claw portion 107 b andthe third lens-side claw portion 107 c that are apart from each other tosome extent, in other words, the lock pin groove portion 102 is providedin a region including some space. And, as described above, the lock pingroove portion 102 is provided at the third lens-side cutaway 108 c (orat a region where the third lens-side cutaway 108 c provided) betweenthe second lens-side claw portion (the second concave portion sidebayonet claw portion) 107 b and the third lens-side claw portion (thefirst concave portion side bayonet claw portion) 107 c. Accordingly, inthe present exemplary embodiment, when the interchangeable lens assembly100 is mounted on the camera body 200, biasing force from the lock pin203 is received in the region that includes some space. Accordingly, inthe present exemplary embodiment, abrasion in the portion where the lockpin 203 slides in the lens mount 101 can be suppressed more with thebiasing force from the lock pin 203. Furthermore, in the presentexemplary embodiment, the portion between the second lens-side clawportion 107 b and the third lens-side claw portion 107 c, in otherwords, the third lens-side cutaway 108 c is longer than the otherlens-side cutaways; accordingly, the abrasion described above can besuppressed further.

Furthermore, in the present exemplary embodiment,

40°<θ1<70°, and 40°<θ2<70°  (4)

are satisfied.

In other words, in the present exemplary embodiment, the secondlens-side claw portion 107 b and the third lens-side claw portion 107 care disposed 102 in a well-balanced manner with respect to the lock pingroove portion; accordingly, as described above, the interchangeablelens assembly 100 can be mounted on the camera body 200 in a furtherstable manner. The upper limit of conditional expression (4) may be 60°.

Furthermore, since the second lens-side claw portion 107 b and the thirdlens-side claw portion 107 c overlap line L2 that is a boundary line,the second lens-side claw portion 107 b and the third lens-side clawportion 107 c can be disposed in a well-balanced manner with respect tothe lock pin groove portion 102.

Disposition of Bayonet Claw Portions of Camera-Side Mount

Referring next to FIG. 4A, a phase (disposition) of the camera-side clawportions of the camera mount 201 will be described. FIG. 4A is a diagramof the camera mount 201 in a normal position state viewed from the imagepickup plane side of the camera body 200.

As illustrated in FIG. 4A, when viewed in the optical axis O direction,the camera mount 201 includes a first camera-side claw portion (a thirdbayonet claw portion) 208 a, the second camera-side claw portion (afourth bayonet claw portion) 208 b, and a third camera-side claw portion(a fifth bayonet claw portion) 208 c that have dimensions in a radialdirection and a circumferential direction of an opening included in thecamera mount 201. The first camera-side claw portion 208 a, the secondcamera-side claw portion 208 b, and the third camera-side claw portion208 c are a plurality of first engagement portions included in thecamera body 200. Furthermore, the camera mount 201 includes acamera-side diameter fitting portion 210 that becomes a restriction in adirection orthogonal to the optical axis when the lens mount 101 isattached to the camera mount 201. When the lens mount 101 is attached tothe camera mount 201, the above camera-side diameter fitting portion 210and the lens-side diameter fitting portion 109 described above arediametrically fitted to each other.

Note that in the description hereinafter, a portion between the thirdcamera-side claw portion 208 c and the first camera-side claw portion208 a is referred to as a first camera-side cutaway 209 a, and a portionbetween the first camera-side claw portion 208 a and the secondcamera-side claw portion 208 b is referred to as a second camera-sidecutaway 209 b. Furthermore, a portion between the second camera-sideclaw portion 208 b and the third camera-side claw portion 208 c isreferred to as a third camera-side cutaway 209 c. Furthermore, one endof the first camera-side claw portion 208 a is referred to as a firstcamera-side end 208 a 1 and the other end is referred to as a secondcamera-side end 208 a 2. Furthermore, camera-side ends of thecamera-side claw portions in the clockwise direction in FIG. 4A from thesecond camera-side end 208 a 2 are referred to as a third camera-sideend 208 b 1, a fourth camera-side end 208 b 2, a fifth camera-side end208 c 1, and a sixth camera-side end 208 c 2.

In the present exemplary embodiment, among the camera-side clawportions, the first camera-side claw portion 208 a is positioned on asubstantially opposite side of the lock pin 203 with the optical axis Oin between when the camera mount 201 at the normal position is viewedfrom the photographer side.

Operation of Attaching Interchangeable Lens Assembly 100 to Camera Body200

Referring next to FIGS. 5 and 6, an operation of attaching theinterchangeable lens assembly 100 to the camera body 200 will bedescribed. FIG. 5 is a diagram of the lens mount 101 and the cameramount 201 in the insertion/removal state and at the normal positionviewed from the image pickup member 202 side, and FIG. 6 is a diagram ofthe lens mount 101 and the camera mount 201 in the mounted state and atthe normal position viewed from the image pickup member 202 side.

The interchangeable lens assembly 100 is mounted on the camera body 200by, first, matching the phases of the camera-side claw portions and thelens-side cutaways so that the interchangeable lens assembly 100 and thecamera body 200 are in a state (the insertion/removal state) in whichthe phases of the camera-side cutaways and the lens-side claw portionsmatches each other. Furthermore, in the above insertion/removal state,the lens-side diameter fitting portion 109 and the camera-side diameterfitting portion 210 are diametrically fitted to each other, and theinterchangeable lens assembly 100 is inserted into the camera body 200to a position where a contact surface on a lens mount 101 side and acontact surface on the camera mount 201 side abut against each other.

When the interchangeable lens assembly 100 is fully inserted in thecamera body 200, the interchangeable lens assembly 100 is rotated about60° (in a direction illustrated by an arrow in FIG. 5) relative to thecamera body 200 from the phase in the insertion/removal state towardsthe phase in the mounted state. As a result of the above operation,mounting of the interchangeable lens assembly 100 on the camera body 200is completed. In the phase in the mounted state, when viewed in theoptical axis direction, the camera-side claw portions and the lens-sideclaw portions overlap each other. In other words, since both members arebayonet coupled to each other, the interchangeable lens assembly 100 canbe prevented from coming off from the camera body 200 in the opticalaxis direction.

More specifically, in the mounted state, the first lens-side clawportion 107 a is positioned on the image pickup member 202 side of thefirst camera-side claw portion 208 a, and the second lens-side clawportion 107 b is positioned on the image pickup member 202 side of thesecond camera-side claw portion 208 b. Furthermore, the third lens-sideclaw portion 107 c is positioned on the image pickup member 202 side ofthe third camera-side claw portion 208 c. Accordingly, separation in theoptical axis direction does not occur as long as the lock pin 203 doesnot come off from the lock pin groove portion 102. Furthermore, in theabove, since the lens-side claw portions being biased (pulled in) in animage pickup member 202 direction by the lens mount biasing member 207are moved to one side, a space between the camera body 200 and theinterchangeable lens assembly 100 in the optical axis direction issuppressed from being created.

Influence Lock Pin 203 being Retreated has Between Insertion/RemovalState and Transition State

In the fitting operation described above, the lock pin 203 is pressed bythe lens mount 101 and the lock pin 203 is pressed against the lensmount 101 at all times in the insertion/removal state and in atransition state between the insertion/removal state and the mountedstate. When in the mounted state, the lock pin 203 is inserted into thelock pin groove portion 102, and the lock pin 203 is brought to anadvanced state from a retreated state.

In other words, in the insertion/removal state and in the transitionstate, force that separates the lens mount 101 and the camera mount 201from each other is applied between the two mounts. Accordingly, the twomounts need to be pressed against each other with the force of the userduring the transition between the transition state and theinsertion/removal state. In other words, both mounts need to be pressedagainst each other with force that is equivalent to or larger than thebiasing force of the lock pin 203 until engaging between the lens-sideclaw portions and the camera-side claw portions start. Furthermore, inthe transition state, the biasing force of the lock pin 203 iscontinuously applied, without change, to a lock pin traveling surface110 (a broken-line portion in FIG. 3) of the lens mount 101.

Since the lock pin 203 needs to have strength, a material with highhardness is used in many cases, and stainless steel is used in thepresent exemplary embodiment as well. On the other hand, a material thatis inferior in strength is used for the lens mount 101 in many casesand, for example, an aluminum alloy, a copper alloy including brass, aresin member, or another metal material is typically used. Accordingly,when operations of attaching and detaching the interchangeable lensassembly 100 to and from the camera body 200 are repeated, degradationssuch as the appearance being damaged due to abrasions and scratchesoccurring on the lens mount 101, an increase in the sliding friction,and a deterioration in flatness may occur.

Note that in the present exemplary embodiment, as a measure against thedeterioration in flatness, a difference in level is provided between thelock pin traveling surface 110 and a contact surface 111 between thelens mount 101 and the camera mount 201. With the above, accuracy in theabutment between the lens mount 101 and the camera mount 201 isobtained, and occurrence of deterioration in flatness is suppressed.

Reducing the biasing force of the lock pin 203 can be conceived as ameasure to suppress abrasions and scratches from occurring. However, ifthe biasing force of the lock pin 203 is reduced, there is a risk of themounted state becoming released when, in the mounted state, the usertouches the release operation member 204 due to carelessness or when, inthe mounted state, a vibration is applied to the mounts. Accordingly,while not reducing the biasing force itself against the lock pin 203,the influence of the biasing force, which is applied to the lock pin203, needs to be suppressed.

Configuration that Suppresses Influence of Biasing Force of Lock Pin 203

Referring now to FIG. 6, an angle formed by a point that is nearest tothe lock pin 203 in the range (the region) where the third lens-sideclaw portion 107 c and the third camera-side claw portion 208 c overlapeach other, the optical axis O, and the center of the lock pin 203 orthe center of the lock pin groove portion 102 is assumed to be θ5. Inthe present exemplary embodiment, the point that is nearest to the lockpin 203 is a point on the fifth lens-side end 107 c 1. Furthermore, anangle formed by a point that is nearest to the lock pin 203 in the rangewhere the second lens-side claw portion 107 b and the second camera-sideclaw portion 208 b overlap each other, the optical axis O, and thecenter of the lock pin 203 is assumed to be θ6. In the present exemplaryembodiment, the point that is nearest to the lock pin 203 is a point onthe fourth camera-side end 208 b 2.

Note that the point that is nearest to the lock pin 203 or the lock pingroove portion 102 in the range (region) in which the lens-side clawportions and the camera-side claw portions overlap each other is a pointon an end of the lens-side claw portion or an end of the camera-sideclaw portion. The end of the lens-side claw portion or the end of thecamera-side claw portion herein may be a middle point in the end of theclaw portion. Alternatively, the point on the end of the lens-side clawportion or the end of the camera-side claw portion may be anintersection between the end of the lens-side claw portion and an outerperipheral surface or an inner peripheral surface or the camera-sideclaw portion. Alternatively, the point on the end of the lens-side clawportion or the end of the camera-side claw portion may be anintersection between the end of the camera-side claw portion and anouter peripheral surface or an inner peripheral surface or the lens-sideclaw portion.

Note that assuming that A is a difference in dimensions in the opticalaxis direction defined by the lens-side claw portions and thecamera-side claw portions, when the mounts move parallel to each other,the space component in the optical axis direction between the mountsremains to be A. Furthermore, the direction in which the mounts tend totilt is determined by the angle at which the claw portions overlap eachother, in other words, by the size of the area in which the lens clawportions and the camera claw portions overlap each other. In otherwords, the intermediate point between the ranges (or the regions) wherethe lens-side claw portions and the camera-side claw portions overlapeach other is the direction in which the mounts tilt most easily.Vertexes of a hexagon illustrated by a broken line in FIG. 6 are pointsthat practically restrict the tilting of the mounts. The tilting nearthe center of each side of the hexagon is large, and as the side becomeslonger, the absolute value of the tilting in the direction towards theside becomes larger.

Note that two of the vertexes of the hexagon illustrated in FIG. 6 canbe paraphrased as a first end and a second end of the region where thefirst inserted-portion-side engagement portion and a thirdimage-pickup-apparatus-side engagement portion overlap each other. Theother vertexes can be paraphrased in a similar manner.

In the present exemplary embodiment, among the ranges in which thelens-side claw portions and the camera claw portions overlap each other,the range between the fourth camera-side end 208 b 2 and the fifthlens-side end 107 c 1, in other words, the range including the angleθ5+θ6 is the largest. In other words, among the sides of the hexagonillustrated in FIG. 6, the side between the fourth camera-side end 208 b2 and the fifth lens-side end 107 c 1 is the longest. In other words, inthe present exemplary embodiment, the range in which tilting of the lensmount 101 relative to the camera mount 201 occurs most easily is therange between the fourth camera-side end 208 b 2 and the fifth lens-sideend 107 c 1.

As in the present exemplary embodiment, among the ranges in which thelens-side claw portions and the camera claw overlap each other, the lockpin 203 is provided in the range having the widest angle and in whichthe lens mount 101 relatively tilts most easily (in which a space iscreated most easily). Accordingly, even if the biasing force of the lockpin 203 is not reduced, abrasion of the surface of the lens mount 101can be suppressed with the biasing force of the lock pin 203.

Note that while the description given above uses angle θ5 and angle θ6formed when the interchangeable lens assembly 100 and the camera body200 are in the mounted state illustrated in FIG. 6, angle θ5 changes inthe course of reaching the mounted state from the insertion/removalstate through the transition state. Accordingly, in each state, thesmallest θ5 is defined as θ7, and the smallest θ6 is defined as θ8. Inthe present exemplary embodiment, θ7=54°, and θ8=46°.

Note that θ5 is always determined by the fifth lens-side end 107 c 1,the optical axis O, and the lock pin 203, and changes in the course ofreaching the mounted state from the insertion/removal state through thetransition state. The state in which θ5 is at its minimum value is themounted state. Meanwhile, θ6 is always determined by the fourthcamera-side end 208 b 2, the optical axis O, and the lock pin 203, doesnot change in the course of reaching the mounted state from theinsertion/removal state through the transition state, and is alwaysfixed, that is, θ6=θ8 at all times. In the present exemplary embodiment,the interchangeable lens assembly 100 is configured so as to satisfy

0.75≤θ7/θ8≤1.25,  (8)

or

0.80≤θ7/θ8≤1.20.  (8a)

In the present exemplary embodiment, θ7/θ8=1.17, and conditionalexpression (8) described above are satisfied. By having theinterchangeable lens assembly 100 satisfy conditional expression (8),the state in which θ5+θ6 is the smallest is achieved. And, in thismounted state, the lock pin 203 is positioned at substantially themiddle in the range between the fifth lens-side end 107 c 1 and thefourth camera-side end 208 b 2.

In other words, in the mounted state, the lock pin 203 is positioned inthe direction (the position) in which the lens mount 101 tilts easily.Accordingly, the influence of the biasing force of the lock pin 203 inthe mounted state in which the biasing force becomes the strongest canbe suppressed. Furthermore, the interchangeable lens assembly 100 can bemounted on the camera body in a more stable manner. In the presentexemplary embodiment θ7 is larger than θ8.

Furthermore, in the present exemplary embodiment, the interchangeablelens assembly 100 satisfies

90°<θ7+θ8<180°, and 90°<θ9+θ8<180°,  (9)

or

90°<θ7+θ8<110°, and 140°<θ9+θ8<170°.   (9a)

As illustrated in FIG. 6, θ9 is an angle formed by the sixth camera-sideend 208 c 2, the optical axis O, and the center of the lock pin 203, andis the maximum value of θ5.

When the interchangeable lens assembly 100 satisfies conditionalexpression (9) from the time the interchangeable lens assembly 100 isattached to the camera body 200 until the mounting of theinterchangeable lens assembly 100 on the camera body 200 is completed,the following effect can be obtained. The lock pin 203 is alwayspositioned in the region where the interval between the points in whichthe lens-side claw portions and the camera-side claw portions are incontact with each other is wide. Accordingly, since, from theinsertion/removal state to the transition state, the lock pin 203 isalways in a state in which tilting easily occurs, even if the biasingforce of the lock pin 203 is not weakened, the influence of the biasingforce of the lock pin 203 can be suppressed. In the present exemplaryembodiment, θ7+θ8=100° and θ9+θ8=160° are satisfied.

Furthermore, θ7 and θ8 are both 45 degrees or larger, and the lock pin203 is positioned away from the positions where the claw portions, whichare tilting restricting members, overlap each other; accordingly, thelock pin 203 is more likely to become tilted.

By having the above configuration, the tilting of the lock pin 203 inthe phase direction (circumferential direction) can be made large, themounts are separated from each other by the biasing force of the lockpin 203, and the biasing force of the lock pin 203 in the transitionstate is weakened; accordingly, abrasion and scratching can besuppressed from occurring. Furthermore, in the mounted state, by biasingthe lens-side claw portions with the lens mount biasing member 207 withforce that is larger than the biasing force of the lock pin 203, thespace created during the mounted state can be suppressed.

Dispositional Relationship Between Lock Pin Groove Portion and Lens SideClaw Portions

While the dispositional relationship between the lock pin groove portionand the lens-side claw portions has been described with reference toFIG. 3, the dispositional relationship between the lock pin grooveportion and the lens-side claw portions according to the presentexemplary embodiment can be described in the following manner withreference to FIGS. 7, 8A, and 8B.

As described above, the lens-side claw portions are biased in the imagepickup member 202 direction with the lens mount biasing member 207. Withthe above biasing force, creation of the space between theinterchangeable lens assembly 100 and the camera body 200, in otherwords, the space between the lens mount 101 and the camera mount 201 issuppressed. Furthermore, the biasing force generates frictional forcebetween the lens mount 101 and the camera mount 201, and suppresses thespace in the radial direction orthogonal to the optical axis directionfrom being created and the lens mount 101 from being relativelydisplaced in the radial direction with respect to the camera mount 201.Furthermore, the space in the radial direction and the relativedisplacement are also suppressed by, as described above, inserting thelock pin 203 in the lock pin groove portion 102.

Supposedly, if such biasing force concentrates on a single lens clawportion, there will be a concern that the lens mount 101 and,consequently, the interchangeable lens assembly 100 will tilt in thedirection where the lens claw portion is located. Accordingly, it isdesirable that the biasing force of the lens mount biasing member 207acts on the lens mount 101, in other words, the interchangeable lensassembly 100 in a uniform manner. Accordingly, in the present exemplaryembodiment, the lens claw portions that receive the biasing force fromthe lens mount biasing member 207 are disposed in a substantiallyuniform manner. Hereinafter, the disposition will be described indetail.

Referring to FIG. 7, the center of the first lens-side claw portion 107a is referred to as a first lens-side claw portion center 107 a 3, thecenter of the second lens-side claw portion 107 b is referred to as asecond lens-side claw portion center 107 b 3, and the center of thethird lens-side claw portion 107 c is referred to as a third lens-sideclaw portion center 107 c 3. In other words, the suppression of thespace between the lens mount 101 and the camera mount 201 is achievedthrough frictional force and position restriction by, mainly, the lockpin groove portion center 102 a, in addition to the three lens-side clawportion centers 107 a, 107 b 3, and 107 c 3. Accordingly, by disposingthe above centers on the lens mount 101 in a substantially uniformmanner, the frictional force generated between the lens mount 101 andthe camera mount 201 can be equalized. By adopting the aboveconfiguration in the present exemplary embodiment, the interchangeablelens assembly 100 can be mounted on the camera body 200 in a furtherstable manner.

Note that the definitions of the lens-side claw portion centers and thelock pin groove portion center 102 a will be described with reference toFIGS. 8A and 8B. Specifically, first, as illustrated in FIG. 8A, line L7is a line that passes the point that equally divides the dimension ofthe lens-side claw portion into two in the circumferential direction, inother words, a point where dimensions c1 and c2 are the same in thecircumferential direction, and the optical axis O. Furthermore, line L8is a curved line that passes a point that equally divides the dimensionof the lens-side claw portion into two in the radial direction, in otherwords, line L8 is a curved line in which dimensions d1 and d2 are thesame in the radial direction. In the above, the intersection betweenline L7 and line L8 is assumed to be the center of the lens-side clawportion. The above dimension of the lens-side claw portion in the radialdirection is a dimension from a point P1 or P2 where the lens-side clawportion stands in a portion of the lens mount 101 to the outerperipheral surface of the lens-side claw portion. Furthermore, thecenter of the lens-side claw portion may be an intersection of twodiagonal lines of a quadrangle formed by connecting four points, thatis, two points P1 and P2 where the lens-side claw portion stands and twopoints at the ends of the outer peripheral surface of the lens-side clawportions.

Furthermore, the lock pin groove portion center 102 a is as illustratedin FIG. 8B. Specifically, first, line L9 is a line that passes a pointthat equally divides the dimension of the lock pin groove portion 102into two in the line L1 direction, in other words, a line that passes apoint where the dimensions h1 and h2 are the same in the line L1direction, and is a line that is orthogonal to line L1. In the above,the intersection between line L9 and line L1 is assumed to be the lockpin groove portion center 102 a. Note that line L1 is also a line thatequally divides the dimension of the lock pin groove portion 102 intotwo in the line L9 direction, in other words, line L1 is a line thatpasses a point where dimensions v1 and v2 are the same in the line L8direction.

Referring next to FIG. 7, the configuration of disposing theabove-described centers of the lens mount 101 in a substantially uniformmanner will be described in a more specific manner. FIG. 7 illustrates aquadrangle having the lens-side claw portion centers 107 a 3 to 107 c 3and the lock pin groove portion center 102 a as the vertexes, andinternal angles of the quadrangle.

Note that among the internal angles, θ10 is an angle of a first internalangle having the first lens-side claw portion center 107 a 3 as itsvertex, θ20 is an angle of a second internal angle having the secondlens-side claw portion center 107 b 3 as its vertex, θ30 is an angle ofa third internal angle having the third lens-side claw portion center107 c 3 as its vertex, and θL is an angle of a fourth internal anglehaving the lock pin groove portion center 102 a as its vertex. In thepresent exemplary embodiment, the angles of the internal angles are setso that the lens-side claw portion centers and the lock pin grooveportion center are disposed in a substantially uniform manner. Sinceθ10, θ20, θ30, and θL are internal angles of the quadrangle,θ10+θ20+θ30+θL=360° is satisfied. More specifically, the interchangeablelens assembly 100 according to the present exemplary embodimentsatisfies

75°≤θ10≤105°,75°≤θ20≤105°,75°≤θ30≤105°,

and

75°≤θL≤105°.  (10)

In other words, since each of θ10, θ20, θ30, and θL falls within apredetermined angle range, as described above, the lens-side clawportion centers and the lock pin groove portion center are disposed in asubstantially uniform manner. Note that conditional expression (10) maybe expressed as

60°≤θ10≤120°,60°≤θ20≤120°,60°≤θ30≤120°, and 60°≤θL≤120°.  (10a)

Alternatively, conditional expression (10) may be expressed as

60°≤θ10≤100°,60°≤θ20≤100°,60°≤θ30≤100°, and 60°≤θL≤100°  (10b)

or

65°≤θ10≤100°,65°≤θ20≤100°,65°≤θ30≤100°, and 65°≤θL≤100°  (10c)

or

70°≤θ10≤100°,70°≤θ20≤100°,70°≤θ30≤100°, and 70°≤θL≤100°.  (10d)

Note that the upper limits of conditional expressions (10b), (10c) and(10d) may be 99°.

Furthermore, it is preferable that at least either one of θ10, θ20, θ30,and θL is in the range of 85 degrees to 95 degrees, inclusive, since thelens-side claw portion centers and the lock pin groove portion centerare disposed in a further substantially uniform manner.

It is more preferable that the interchangeable lens assembly 100satisfies

85°≤θL≤95°  (11)

or

90°<θL≤95°  (11a)

since the lens-side claw portion centers are disposed in a furtheruniform manner with respect to the lock pin groove portion center 102 a.

Most preferably, the interchangeable lens assembly 100 satisfies

0.75≤θ30/θ20≤1.25  (12)

or

0.85≤θ30/θ20≤1.15  (12a)

or

0.95≤θ30/θ20≤1.05.  (12b)

The above is preferable since the second lens-side claw portion 107 band the third lens-side claw portion 107 c are disposed in a uniformmanner with respect to the lock pin groove portion 102. Furthermore, ifθL is larger than 90°, in other words, if θL is an obtuse angle, thethird lens-side cutaway 108 c will be longer than the other lens-sidecutaways; accordingly, the influence of the biasing force of the lockpin 203 can be suppressed. In the present exemplary embodiment, θ20 islarger than θ30.

Note that regarding the internal angles in the present exemplaryembodiment, θ10=77°, θ20=98°, θ30=92°, and θL=93°, and theinterchangeable lens assembly 100 satisfies the conditions describedabove related to the internal angles. As described above, in the presentexemplary embodiment, the center points are disposed on the lens mount101 in a substantially uniform manner. Accordingly, the frictional forcegenerated between the lens mount 101 and the camera mount 201 can beequalized, and the interchangeable lens assembly 100 can be mounted onthe camera body 200 in a further stable manner while suppressing thespace from being created.

In many cases, when in the state in which the interchangeable lensassembly 100 is mounted on the camera body 200, the interchangeable lensassembly 100 is operated while holding the camera body 200. Accordingly,there are cases in which force in the radial direction, which is adirection perpendicular to the optical axis direction, is appliedbetween the lens mount 101 and the camera mount 201. Conversely, sincethe present exemplary embodiment employs the configuration describedabove, the interchangeable lens assembly 100 can be mounted on thecamera body 200 in a further stable manner. Accordingly, when high-speedconsecutive photographing is carried out or when a moving image istaken, positional displacement between each frame caused by the spacebetween the lens mount 101 and the camera mount 201 does not easilyoccur.

In recent years, achievements of high-resolution in image pickup membersare becoming noticeable, such as a sensor having 250 million pixelsbeing developed in APS-H size (about 29.2×20.2 mm) sensors. As the imagebecomes higher in resolution, positional displacement becomes moreconspicuous when the image of each frame is checked. With regards tosuch a situation, the present exemplary embodiment is capable ofsuppressing positional displacement even when the image pickup memberachieves higher resolution.

Note that in order to suppress the space between the lens mount 101 andthe camera mount 201 in the radial direction from being created, one mayconceive of tightening the fit between the lens-side diameter fittingportion 109 and the camera-side diameter fitting portion 210. However,if the fit between the lens-side diameter fitting portion 109 and thecamera-side diameter fitting portion 210 is tightened, the workefficiency of attaching the lens mount 101 and the camera mount 201 toeach other decreases. Conversely, by employing the configuration of thepresent exemplary embodiment, there will be no need to tighten the fitbetween the lens-side diameter fitting portion 109 and the camera-sidediameter fitting portion 210; accordingly, the decrease in the workefficiency described above can be suppressed.

Furthermore, in order to suppress the space between the lens mount 101and the camera mount 201 in the radial direction from being created, onemay conceive of increasing the biasing force generated by the lens mountbiasing member 207. However, if the biasing force generated by the lensmount biasing member 207 is increased, operating force when the lensmount 101 and the camera mount 201 are in the insertion/removal stateneeds to be increased. Conversely, by employing the configuration of thepresent exemplary embodiment, there will be no need to increase thebiasing force generated by the lens mount biasing member 207;accordingly, a large operating force described above will be not need.

Modifications

While a preferable embodiment of the present disclosure has beendescribed above, the present disclosure is not limited to the embodimentand may be deformed and modified within the gist of the presentdisclosure.

For example, as long as the configuration of the present exemplaryembodiment is used in optical apparatuses (accessories), theconfiguration can be used in camera accessories other thaninterchangeable lens assemblies used with a mount such as an adapter oran extender interposed in between. Furthermore, the claw portions mayeach be provided with a cutaway or a step portion. Furthermore, theconfiguration described in the present exemplary embodiment can be usedin lens barrels for various image pickup devices other than theinterchangeable lens assembly for a single-lens reflex camera, such as alens shutter camera, a digital camera, and a video camera. In both theinterchangeable lens assembly 100 and the adapters, a member in whichthe lens mount 101 is fixed with the lens mount fixing members 103 isthe accessory main body.

Note that in the present exemplary embodiment, while θ7 is practicallydetermined by the fifth lens-side end 107 c 1, depending on the anglerange of the third lens-side claw portion 107 c or the third camera-sideclaw portion 208 c, θ7 may be determined by the fifth camera-side end208 c 1.

Furthermore, the three bayonet claw portions provided in the mounts inthe exemplary embodiment described above may each be divided so as to befurther divided into segments. In other words, a single bayonet clawportion may be formed as a collection of a plurality of bayonet clawportions (a group of bayonet claw portions). For example, the abovecorresponds to a case in which a groove portion is provided in a singlebayonet claw portion. In such a case, the angle range of the group ofbayonet claw portions arranged in the circumferential direction of eachmount is as in the exemplary embodiment described above.

Referring now to FIGS. 9A and 9B, a description of a plurality ofelectrical contacts (terminal units or electrical contacts units)included in the lens contact portions (lens-side terminals) holdingmember 105 will be given. FIG. 9A is a block diagram of the camerasystem viewed in a manner different from that of FIG. 1 described above.A lens 601 in FIG. 9A is the optical elements in FIG. 1, such as thezoom lens unit ZLU and the focus lens unit FLU. A lens control unit 603is the lens CPU in FIG. 1, and a mount 600 is a collective term for thelens mount 101 and the camera mount 201. A lens drive unit 602 is acollective term for the driving members in FIG. 1, and an image sensor611 is the image pickup member 202 in FIG. 1. A lens control unit 603 iscapable of performing first, second, and third communication between acamera control unit 618 through terminals described later.

The camera body 200 includes an A/D conversion unit 612 that converts ananalog electrical signal output from the image sensor 611 into a digitalsignal, and an image processor 613 that generates an image signal byperforming various types of image processing on the digital signalconverted by the A/D conversion unit 612.

The image signal (a still image or a moving image) generated with theimage processor 613 is displayed on a display unit 614 or is recorded ina recording medium 615. Furthermore, the camera body 200 includes amemory 616 that functions as a buffer when processing is performed onthe image signal. The memory 616 stores an operation program used by thecamera control unit 618 described later. The camera body 200 furtherincludes a camera operation input unit 617 including a power switch thatturns the power source on and off, a photographing switch that startsrecording of an image signal, and a selecting/setting switch to performsetting of various menus.

The camera body 200 further includes the camera control unit 618 thatincludes a microcomputer. The camera control unit 618 performs varioussettings based on signals input from the camera operation input unit617, and controls the communication between the lens control unit 603included in the interchangeable lens assembly 100 through the mount 600.

Referring next to FIG. 9B, a configuration of the electrical connectionbetween the camera body 200 and the interchangeable lens assembly 100will be described. FIG. 9B illustrates an electric circuit configurationwhen the camera body 200 and the interchangeable lens assembly 100 areconnected to each other through the mount 600, terminals (electricalcontacts) provided in the mount 600 to electrically connect the camerabody 200 and the interchangeable lens assembly 100 to each other, and astate in which the terminals are connected to each other.

The mount 600 in the camera system includes a mount portion (a firstmount portion) A on the camera body 200 side and a mount portion (asecond mount portion) B on the interchangeable lens assembly 100 side.The mount portion A and the mount portion B include a plurality ofterminals (contact points or electrical contacts) that are capable ofbeing electrically connected to the counterparts.

More specifically, the mount 600 includes VDD terminals and VBATterminals that supply power to the interchangeable lens assembly 100from the camera body 200, DGND terminals and PGND terminals that areground terminals. The mount 600 further includes LCLK terminals, DCLterminals, DLC terminals, DLC2 terminals, CS terminals, and DCAterminals that are communication terminals for the camera control unit618 and the lens control unit 603 to communicate with each other. Asother terminals, the mount 600 further includes MIF terminals thatdetect that the interchangeable lens assembly 100 has been mounted onthe camera body 200, and TYPE terminals that distinguish the type ofcamera accessory that has been mounted on the camera body 200.

Hereinafter, a more detailed description of the terminals will be given.

Power Terminals

The VDD terminals are terminals that supply communication control power(VDD), which is communication power used mainly to controlcommunication, to the interchangeable lens assembly 100 from the camerabody 200. In the present exemplary embodiment, the communication controlpower is 5.0 V. The VBAT terminals are terminals that supply drivingpower (VBAT), which is driving power used in operations other than theabove communication control, such as operations of mechanical drivesystems and the like mainly including a motor and the like, to theinterchangeable lens assembly 100 from the camera body 200. In thepresent exemplary embodiment, the driving power is 4.25 V.

The DGND terminals are terminals that connect the communication controlsystems of the camera body 200 and the interchangeable lens assembly 100to the ground. In other words, the DGND terminals are ground (GND)terminals corresponding to the VDD power source described above.Grounding herein is setting to a level that is the same as the level ofthe negative electrode-side of the power source such as a battery. ThePGND terminals are terminals that connect the camera body 200 and themechanical drive system, such as a motor, provided in theinterchangeable lens assembly 100 to the ground. In other words, thePGND terminals are terminals that correspond to the VBAT power sourcedescribed above.

Communication Terminals

The communication terminals include a terminal unit (the LCLK, DCL, andDLC terminals) that is a first communication unit that performs thefirst communication, and terminals (the DLC2 terminals) that are asecond communication unit that performs the second communicationindependent of the first communication. The communication terminalsfurther include a terminal unit (the CS, and DCA terminals) that is athird communication unit that performs the third communicationindependent of the first and second communications. The camera controlunit 618 and the lens control unit 603 are capable of performing thefirst, second, and third communications that are independent of eachother through the above communication terminals.

The LCLK terminals are terminals for communication clock signals outputfrom the camera body 200 to the interchangeable lens assembly 100, andare also terminals in which the camera body 200 monitors a busy state ofthe interchangeable lens assembly 100. The DCL terminals are terminalsfor two-way communication data between the camera body 200 and theinterchangeable lens assembly 100, and are CMOS interfaces. The DLCterminals are terminals for communication data that is output from theinterchangeable lens assembly 100 to the camera body 200, and are CMOSinterfaces.

The DLC2 terminals are terminals for communication data that is outputfrom the interchangeable lens assembly 100 to the camera body 200, andare CMOS interfaces. The DCA terminals are terminals for two-waycommunication data between the camera body 200 and the interchangeablelens assembly 100, and are CMOS interfaces. The CS terminals areterminals for a communication request signal between the camera body 200and the interchangeable lens assembly 100, and are open interfaces.

Other Terminals

MIF terminals are terminals for detecting whether the interchangeablelens assembly 100 has been mounted on the camera body 200, and whetherthe interchangeable lens assembly 100 has been dismounted from thecamera body 200. After detecting that the interchangeable lens assembly100 has been mounted on the camera body 200 by detecting the change inthe voltage level of the MIF terminals, the camera control unit 618starts supplying power to the VDD terminals and the VBAT terminals, andstarts communication. In other words, the MIF terminals are triggersthat start the supply of power from the camera body 200 to theinterchangeable lens assembly 100. As described above, the TYPEterminals are terminals that distinguish the type of camera accessorymounted on the camera body 200. The camera control unit 618 detects thevoltages of the signals of the TYPE terminals, and based on the value ofthe voltages, distinguishes the type of camera accessory mounted on thecamera body 200. The interchangeable lens assembly 100 is pull-downconnected to the DGND terminals at a predetermined resistance valuedescribed later. In the present exemplary embodiment, in a case in whichthe interchangeable lens assembly 100 is mounted on the camera body 200,communication is performed while the interface voltages of the firstcommunication unit, the second communication unit, and the thirdcommunication unit are set to 3.0 V.

Furthermore, in the exemplary embodiment described above, aconfiguration has been described in which a device that includes eitherone of the camera mount and the accessory mount is actually rotatedrelative to a device that includes the other one of the camera mount andthe accessory mount to bayonet couple the devices to each other;however, the configuration is not limited to the above configuration.For example, a configuration that allows the camera mount and theaccessory mount to be bayonet coupled to each other by having the cameramount and the accessory mount be relatively rotated against each othermay be employed. Hereinafter, the detail of the above will be describedspecifically.

FIG. 10 is an exploded perspective view of a mount mechanism 5000according to a modification of the present disclosure. FIGS. 11A to 11Care diagrams that exemplify a non-connected state of the mount mechanism5000 according to the modification of the present disclosure. FIGS. 12Ato 12C are diagrams that exemplify a connected state of the mountmechanism 5000 according to the modification of the present disclosure.Note that in FIGS. 10 to 12C, for the sake of description, a movablemount portion 5010 of the mount mechanism 5000, and a lens mount 101that is capable of being bayonet coupled to the movable mount portion5010 of the mount mechanism 5000 are illustrated at the same time.Furthermore, description of members that are the same as those of theexemplary embodiment is omitted and the same reference numerals areattached to the members.

As illustrated in FIG. 10, in the mount mechanism 5000 of the presentmodification, an operation portion 5030, a fixed mount portion 5020, themovable mount portion 5010, a contact point holding member 2030 thathave an optical axis 3000 as the central axis are disposed in that orderfrom the side on which the lens mount 101 is attached. The operationportion 5030 is a ring-shaped operation member rotatable about thecentral axis, and is connected to the movable mount portion 5010 witharm portions 5040 and screws. Note that in the present modification, theoperation portion 5030 and the movable mount portion 5010 are fixed toeach other at two portions using two arm portions 5040 disposed in adirection orthogonal to the central axis. With the above configuration,the movable mount portion 5010 is also rotated about the central axis inaccordance with the rotating operation of the operation portion 5030 inan integrated manner.

Movable mount claw portions 5011 a, 5011 b, and 5011 c capable of beingbayonet coupled to bayonet claw portions provided in the lens mount 101are provided in the movable mount portion 5010. Furthermore, a screwportion 5012 threaded about the central axis is provided in the movablemount portion 5010. The state in which the screw portion 5012 and ascrew portion 5022 of the fixed mount portion 5020 described later arescrewed to each other changes in accordance with the rotation of themovable mount portion 5010 about the central axis.

The fixed mount portion 5020 includes a camera mount surface 5021 thatabuts against a mount surface of the lens mount 101, and the screwportion 5022 that is screwed to the screw portion 5012 of the movablemount portion 5010 described above. Different from the movable mountportion 5010 described above, the fixed mount portion 5020 does notrotate about the central axis in accordance with the rotating operationof the operation portion 5030.

Referring next to FIGS. 11A to 12C, a bayonet coupling method of themount mechanism according to the present modification will be described.Note that while in a state in which the bayonet claws are inserted in anopening portion of the operation member 5030 and an opening portion ofthe fixed mount portion 5020, the bayonet claws provided on the lensmount 101 are engageable with the movable mount claw portions 5011 a to5011 c of the movable mount portion 5010. In the state illustrated inFIGS. 11A to 11C, the operation portion 5030 is positioned in theunlocking position. In the above state, while a lens mount surface ofthe lens mount 101 and the camera mount surface 5021 of the fixed mountportion 5020 abut against each other, the claw portions of the lensmount 101 and the claw portions of the movable mount portion 5010 do notengage or overlap each other when viewed in the central axis direction.FIG. 11C is a cross-sectional diagram taken along cross-section XIC-XICin FIG. 11B. FIGS. 12A to 12C illustrate an exemplification of the mountmechanism 5000 in a state in which the rotation operation has beenperformed on the operation portion 5030 from the above state.

In the state illustrated in FIGS. 12A to 12C, the operation portion 5030is positioned in the locking position. In the above state, when viewedin the central axis direction, the claw portions of the lens mount 101and the claw portions of the movable mount portion 5010 overlap eachother to engage with each other in the central axis direction. FIG. 12Cis a cross-sectional diagram taken along cross-section XIIC-XIIC in FIG.12B. As illustrated in FIGS. 11C and 12C, the movable mount portion 5010moves away from the fixed mount portion 5020 in a center axis directionof the mount depend on a non-locking state of the mount mechanism 5000changing in a lock state of the mount mechanism 5000. Furthermore, inthe above state, in accordance with the rotating operation of theoperation member 5030, the state in which the screw portion 5022 of thefixed mount portion 5020 and the screw portion of the movable mountportion 5010 are screwed to each other changes and the movable mountportion 5010 moves in the central axis direction towards the imagepickup apparatus side. With the above configuration, the movable mountclaw portions 5011 a to 5011 c engaged with the bayonet claw portions onthe lens mount 101 side each move towards the image pickup apparatusside.

As described above, in the mount mechanism 5000 of the presentmodification, by having the movable mount portion including the clawportions that can be engaged with the claw portions on the lens mountside be rotated about the central axis, the movable mount portion can bemoved in the central axis direction relative to the fixed mount portion.With such a configuration, in a state in which the lens mount and thecamera-side mount are connected to each other, the mount mechanism 5000of the present modification can reduce the occurrence of the gap (thespace) created between the lens mount and the camera-side mount.

Note that in the modification described above, a configuration in whichthe mount mechanism 5000 is provided on the image pickup apparatus sidehas been described; however, the present disclosure can be applied to,for example, a configuration in which the mount mechanism 5000 isprovided on the camera accessory side such as the interchangeable lensassembly side.

Hereinafter, a more detailed description of the dispositionalrelationship between the terminals and the mount portions will be given.

Referring to FIGS. 13A and 13B, the dispositional relationship betweenthe camera mount 201 and camera-side terminals described above will bedescribed.

FIG. 13A is a diagram of the dispositional relationship between thecamera mount 201, the plurality of terminal pins 203 a to 203 k, and 203m that are the plurality of camera-side terminals (first terminals), anda camera side terminals holding member 2030 viewed from the subject side(a front side of the camera body 10). FIG. 13B is a diagram of thecamera mount 201, the terminal pins 203 a to 203 k, and 203 m, and theholding member 2030 viewed from obliquely above and from the subjectside (the front side of the camera body 10).

As illustrated in FIG. 8A, in the holding member 2030, the terminal pins203 a to 203 k, and 203 m are arranged on a camera terminal pinarrangement line 3001. The terminal pins 203 a to 203 k, and 203 m areeach a movable terminal that can be advanced and retreated in adirection parallel to the optical axis 3000, and are biased towards theinterchangeable lens assembly 100 side with springs (not shown).

The relationship between the terminals illustrated in FIG. 1B describedabove and the terminal pins is as follows. In other words, the terminalpin 203 a is the camera-side VDD terminal, the terminal pin 203 b is thecamera-side VBAT terminal, the terminal pin 203 c is the camera-sideTYPE terminal, the terminal pin 203 d is the camera-side PGND terminal,and the terminal pin 203 e is the camera-side MIF terminal. Furthermore,the terminal pin 203 f is the camera-side DCL terminal, the terminal pin203 g is the camera-side DLC terminal, the terminal pin 203 h is thecamera-side LCLK terminal, the terminal pin 203 i is the camera-sideDLC2 terminal, and the terminal pin 203 j is the camera-side DCAterminal. Furthermore, the terminal pin 203 k is the camera-side CSterminal, the terminal pin 203 m is the camera-side DGND terminal.

As illustrated in FIG. 13B, heights of the terminal pins 203 a, 203 b,203 c, and 203 d in an optical axis 3000 direction are higher thanheights of the terminal pins 203 e, 203 f, 203 g, 203 h, 203 i, 203 j,203 k, and 203 m in the optical axis 3000 direction. The above isbecause the holding member 2030 includes two surfaces that havedifferent heights in the optical axis 3000 direction in which theterminal pins 203 a, 203 b, 203 c, and 203 d are provided in the highersurface and the rest of the terminal pins are provided in the lowersurface.

In other words, all of the terminal pins of the present exemplaryembodiment are not provided in surfaces at the same height. By havingsuch a configuration, the present exemplary embodiment is capable ofsuppressing abrasion of the terminals caused by the camera-sideterminals sliding against the lens-side terminals when theinterchangeable lens assembly 100 is mounted on the camera body 10. Morespecifically, when the interchangeable lens assembly 100 is rotated fromthe locking position to the unlocking position to mount theinterchangeable lens assembly 100 on the camera body 10, there is aperiod in which the terminal pins 203 e to 203 k, and 203 m are not incontact with the lens-side terminals. Accordingly, the abrasion of theterminals described above can be suppressed.

Referring next to FIGS. 14A and 14B, the dispositional relationshipbetween the lens mount 101 and lens-side terminals described above willbe described. FIG. 14A is a diagram of the dispositional relationshipbetween the lens mount 101 in which the interchangeable lens assembly100 is in the lock phase state, the terminal surfaces 303 a to 303 k,and 303 m that are the plurality of lens-side terminals (secondterminals), and the holding member 105 viewed from the photographerside. FIG. 9B is a diagram of the lens mount 101, the terminal surfaces303 a to 303 k, and 303 m, and the holding member 105 viewed fromobliquely above from the photographer side in a case in which theinterchangeable lens assembly 100 is in the lock phase state and inwhich the interchangeable lens assembly 100 is mounted on the camerabody 10.

As illustrated in FIG. 14A, in the holding member 105, the terminalsurfaces 303 a to 303 k, and 303 m are arranged on a lens contact pointarrangement line 3004. The relationship between the terminalsillustrated in FIG. 9B described above and the terminal surfaces is asfollows. In other words, the terminal surface 303 a is the lens-side VDDterminal, the terminal surface 303 b is the lens-side VBAT terminal, theterminal surface 303 c is the lens-side TYPE terminal, the terminalsurface 303 d is the lens-side PGND terminal, and the terminal surface303 e is the lens-side MIF terminal.

Furthermore, the terminal surface 303 f is the lens-side DCL terminal,the terminal surface 303 g is the lens-side DLC terminal, the terminalsurface 303 h is the lens-side LCLK terminal, the terminal surface 303 iis the lens-side DLC2 terminal, and the terminal surface 303 j is thelens-side DCA terminal. Furthermore, the terminal surface 303 k is thelens-side CS terminal, and the terminal surface 303 m is the lens-sideDGND terminal.

As illustrated in FIG. 14B, heights of the terminal surfaces 303 a, 303b, 303 c, and 303 d in the optical axis 3000 direction are lower thanheights of the terminal surfaces 303 e, 303 f, 303 g, 303 h, 303 i, 303j, 303 k, and 303 m in the optical axis 3000 direction. The above isbecause the holding member 105 includes two surfaces that have differentheights in the optical axis 3000 direction in which the terminalsurfaces 303 a, 303 b, 303 c, and 303 d are provided on the lowersurface and the rest of the terminal surfaces are provided on the highersurface. By having the lens-side terminals have the above configurationthat corresponds to the configuration of the camera-side terminalsdescribed above, the abrasion of the terminals described above can besuppressed.

Reference numerals 303 n and 303 q are guiding inclined faces (inducingoblique surfaces) for mounting the interchangeable lens assembly 100 onthe camera body 10 by pushing the terminal pins towards the image pickupmember 202 side when the interchangeable lens assembly 100 is rotated.By providing the guiding inclined faces, the contact pressure againstthe lens mount 101 of the terminal pins provided on the camera body 10side changes in a gentle and stepwise manner; accordingly, deformationof the terminal pins provided on the camera body 10 side can be reduced.

Referring next to FIGS. 15A and 15B, an operation of fitting theinterchangeable lens assembly 100 on the camera body 10 will bedescribed.

The operation of mounting a camera accessory, such as theinterchangeable lens assembly 100, on the camera body 10 can be broadlyseparated into a first operation and a second operation described next.

The first operation is an operation in which the interchangeable lensassembly 100 is inserted into the camera body 10 by setting thepositions of the camera body 10 and the interchangeable lens assembly100 to predetermined positions in the rotation direction so as to allowthe lens claw portions enter the camera cutaways and is an operation inwhich a lens-side diameter fitting portion 109 in FIG. 3B and acamera-side diameter fitting portion 210 in FIG. 4B are diametricallyfitted to each other. Furthermore, the second operation is an operationin which, while the lens-side diameter fitting portion 109 and thecamera-side diameter fitting portion 210 are diametrically fitted toeach other, relatively rotating the camera body 10 and theinterchangeable lens assembly 100 towards the locking position, and isan operation bringing the camera body 10 and the interchangeable lensassembly 100 to a bayonet coupled state.

FIG. 15A is a diagram illustrating an insertion phase state (a firststate) when the camera body 10 is attached to the interchangeable lensassembly 100 of the present exemplary embodiment viewed from the cameramount 201 side (the photographer side). Note that the insertion phasestate refers to a state in which the first lens-side claw portion 107 ais inserted in the second camera-side cutaway 209 b, the secondlens-side claw portion 107 b is inserted in the third camera-sidecutaway 209 c, and the third lens-side claw portion 107 c is inserted inthe first camera-side cutaway 209 a. The lens-side diameter fittingportion 109 and the camera-side diameter fitting portion 210 arediametrically fitted to each other in the above state.

FIG. 15B is a diagram illustrating a lock phase state (a second state)when the camera body 10 is attached to the interchangeable lens assembly100 of the present exemplary embodiment viewed from the camera mount 201side (the photographer side). Note that the lock phase state is a statein which the interchangeable lens assembly 100 is, from the insertionphase state illustrated in FIG. 15A described above, rotated 60° in theclockwise direction when viewed from the subject side of theinterchangeable lens assembly 100 to engage the lens claw portions andthe camera claw portions to each other.

More specifically, in the lock phase state, the first lens-side clawportion 107 a is positioned on the image pickup member 202 side of thefirst camera-side claw portion 208 a, and the second lens-side clawportion 107 b is positioned on the image pickup member 202 side of thesecond camera-side claw portion 208 b. Furthermore, the third lens-sideclaw portion 107 c is positioned on the image pickup member 202 side ofthe third camera-side claw portion 208 c. The lens claw portions and thecamera claw portions are engaged with each other in the above state, andthe lock pin 203 is inserted in the lock pin groove 102; accordingly,rotation of the interchangeable lens assembly 100 is locked.Furthermore, in the lock phase state, the lens claw portions are biasedtowards the image pickup member 202 with the lens mount biasing member2060. Note that in place of the lens mount biasing member 2060, a flatspring portion may be provided in each camera claw portion.

Furthermore, when the interchangeable lens assembly 100 is transitionedfrom the insertion phase state to the lock phase state, the terminalpins on the camera body 10 side are pressed towards the image pickupmember 202 side with the guiding inclined faces 303 n and 303 qdescribed above.

Furthermore, while being continuously pressed, each of the terminal pinson the camera body 10 side come in contact with the correspondingterminal surfaces 303 a to 303 k, and 303 m. Note that the terminal pin203 m and the terminal surface 303 e come in contact with each otherfirst.

As described above, for example, in the present exemplary embodiment,the configuration of the interchangeable lens assembly 100 has beendescribed by exemplifying an interchangeable lens assembly 100 servingas the optical apparatus, however, the optical apparatus of the presentdisclosure is not limited to the interchangeable lens assembly 100. Forexample, an adapter that can be interposed between the interchangeablelens assembly 100 and the camera body 10 may serve as the opticalapparatus (the accessory) of the present disclosure. Hereinafter, a moredetailed description of this adapter will be given. Note that in thefollowing description, a second conversion adapter 70 has a camera mount1201 same as the camera mount 201 of the camera body 10. And, note thatin the following description, a first conversion adapter 40 has a lensmount 1301 same as the lens mount 101 of the first lens 100. And notethat the camera mount 201 and the lens mount 101 have the ring-shaped,but this is not restrictive in the present embodiments. For example, aconfiguration may be employed where this is realized by each of thecamera mount 201 and lens mount 101 have an arc-shaped contact faces,may be employed in the configuration. In other words, a configurationmay be employed where this is realized by the camera mount 201 and thelens mount 101 are lacked a part of the contact face.

Firstly, the basic configuration of a conversion adapter (adapterdevice) that is a camera accessory mountable to the camera mount 201 ofthe above-described camera body 10 will be described with reference toFIGS. 16A through 17B. FIGS. 16A and 16B are diagrams describing a firstconversion adapter 40 that is mountable to the camera body 10, and asecond interchangeable lens assembly 50. FIG. 16A illustrates anexternal perspective view of the second interchangeable lens assembly 50having been mounted to the camera body 10 via the first conversionadapter 40. FIG. 16B illustrates an external perspective view of a statewhere the camera body 10, first conversion adapter 40, and secondinterchangeable lens assembly 50 have each been detached. Note that thesecond interchangeable lens assembly (hereinafter referred to as secondlens) 50 has a lens mount 501 that is short in flange focal distance,but has the same mount diameter as the camera mount 201, as to thecamera body 10. That is to say, the second lens 50 has the same mountdiameter as the above-described first lens 100, but unlike the firstlens 100, is a camera accessory that is not compatible with directmounting to the camera body 10.

FIGS. 17A and 17B are diagrams for describing a second conversionadapter 70 that is mountable to a camera body 60 and the first lens 100.FIG. 17A illustrates an external perspective view of a state where thefirst lens 100 is mounted to the camera body 60 via the secondconversion adapter 70, and FIG. 17B illustrates an external perspectiveview where the camera body 60, second conversion adapter 70, and firstlens 100 have each been detached.

Now, in a case where an interchangeable lens assembly with a long flangefocal distance is directly mounted to an imaging apparatus with a shortflange focal distance, trouble will occur such as the focal point notbeing formed at an accurate position or the like, and imaging a subjectin this way will result in an unnatural image being obtained. Forexample, the above problem will occur if the second lens 50 that has along flange focal distance is mounted to the above-described camera body10.

In the same way, in a case where an interchangeable lens assembly with ashort flange focal distance is directly mounted to an imaging apparatuswith a long flange focal distance, trouble will occur such as the focalpoint not being formed at an accurate position or the like, and imaginga subject in this way will result in an unnatural image being obtained.For example, the above problem will occur if the first lens 100 that hasa short flange focal distance is mounted to the camera body 60 servingas a second imaging apparatus that has a longer flange focal distancethan the above-described camera body 10.

Particularly, the camera body 10 and camera body 60, and the first lens100 and second lens 50, have the same mount diameter, it is difficultfor a user to judge which imaging apparatuses and which interchangeablelens assemblies have flange focal distances that are compatible fordirect mounting.

Accordingly, it is preferable that only interchangeable lens assembliesthat are compatible can be directly mounted to a certain imagingapparatus, so that imaging apparatuses and interchangeable lensassemblies that have mutually incompatible flange focal distances arenot erroneously directly mounted.

Also, in a case of mounting an incompatible interchangeable lensassembly to an imaging apparatus, a conversion adapter needs to beinterposed between the two to adjust the flange focal distance. However,in a case where one side of the conversion adapter is mounted to theimaging apparatus and an interchangeable lens assembly compatible withdirect mounting to the imaging apparatus is mounted to the other side ofthe conversion adapter, the focal point may not be accurately formed, asdescribed above. Accordingly, the one side and other side of theconversion adapter preferably have configurations to restrict imagingapparatuses and camera accessories that are directly mountable.

Specifically, in a case of mounting an interchangeable lens assemblyhaving a long flange focal distance to an imaging apparatus having ashort flange focal distance, a conversion adapter is preferable whereone end side is only mountable to this imaging apparatus, and the otherend side is only mountable to this interchangeable lens assembly. Also,in a case of mounting an interchangeable lens assembly having a shortflange focal distance to an imaging apparatus having a long flange focaldistance, a conversion adapter is preferable where one end side is onlymountable to this imaging apparatus, and the other end side is onlymountable to this interchangeable lens assembly.

The first conversion adapter 40 has the lens mount 1101 attached to anadapter barrel 40 a by fastening screws (omitted from illustration), atone end side in the optical axis direction. This lens mount 1101 is anaccessory mount that is detachable from the camera mount 201 provided tothe camera body 10 described above.

A camera mount 1401 is attached to the adapter barrel 40 a by fasteningscrews (omitted from illustration), at the other end side of the firstconversion adapter 40 in the optical axis direction. This camera mount1401 is a camera mount that is detachable from the lens mount 501 of thesecond lens 50. Note that the camera mount 1401 of the first conversionadapter 40 is attached so that the imaging plane of the imaging sensor11 of the will be situated at a position corresponding to the flangefocal distance of the second lens 50.

The second conversion adapter 70 has the lens mount 1501 attached to anadapter barrel 70 a by fastening screws (omitted from illustration), atone end side in the optical axis direction. This lens mount 1501 is anaccessory mount that is detachable from the camera mount 1401 providedto the camera body 60.

The camera mount 1201 is attached to the adapter barrel 70 a byfastening screws (omitted from illustration), at the other end side ofthe second conversion adapter 70 in the optical axis direction. Thiscamera mount 1201 is a camera mount that is detachable from the lensmount 101 of the first lens 100, as described above.

Note that a first optical member 701 a and a second optical member 701 bare provided to the second conversion adapter 70, between the adapterbarrel 70 a and the lens mount 1501 in the optical axis direction. Thefirst optical member 701 a and second optical member 701 b enable thesecond conversion adapter 70 to extend length of the flange focaldistance of the first lens 100 in accordance with the imaging plane ofthe imaging sensor disposed in the camera body 60. While the opticalmembers have been illustrated as two lenses for the sake of convenience,this is not restrictive.

Next, the angles (phases) at which bayonet claw portions are disposed onthe circumferential direction of the camera mount and lens mount of thefirst conversion adapter 40 will be described with reference to FIG. 18Athrough FIG. 22. FIGS. 18A through 22 are diagrams for exemplarilydescribing displacement angles of bayonet claw portions in the cameramount 1401 provided on one end of the first conversion adapter 40. FIG.18A is a diagram illustrating angle ranges that camera claw portions andcamera cutaways occupy in the circumferential direction of the cameramount 1401 with the lock pin 1401 z as a reference, as viewed from therear face side (camera body 10 side). FIG. 18B is a diagram illustratingangle ranges that multiple camera claw portions 1401 a through 1401 coccupy in the circumferential direction of the camera mount 1401, asviewed from the rear face side (camera body 10 side). FIG. 18C is across-sectional diagram taken along cross-section XVIIIB-XVIIIB in FIG.18B.

The first conversion adapter 40 is a mount adapter used for mounting thesecond lens 50 that has a long flange focal distance to the camera body10 that has a short flange focal distance. Accordingly, it is preferablefor the first conversion adapter 40 to be configured such that thecamera body 60 that has a long flange focal distance cannot be directlymounted to the lens mount 1101, and the first lens 100 that has a shortflange focal distance cannot be directly mounted to the camera mount401. According to this configuration, the positional relation of clawportions and cutaways can be satisfied so that the lens mount 1101provided to one end (first end) of the first conversion adapter 40 andthe camera mount 1401 provided to the other end (second end) cannot eachbe directly mounted.

A first camera claw portion 1401 a, second camera claw portion 1401 b,and third camera claw portion 1401 c, are provided in order, to thecamera mount 1401 in the circumferential direction (inner radialdirection). When viewing the camera mount 1401 from the rear face sideas illustrated in FIG. 18A, the camera claw portion that is provided ata position farthest from the lock pin 401 z is the first camera clawportion 1401 a. The second camera claw portion 1401 b and third cameraclaw portion 1401 c are then consecutively provided in order from thefirst camera claw portion 1401 a in a clockwise direction.

Also, cutaways which are a first camera cutaway 1401 d, second cameracutaway 1401 e, and third camera cutaway 1401 f are provided in order,to the camera mount 1401 in the circumferential direction (inner radialdirection). When viewing the camera mount 1401 from the rear face sideas illustrated in FIG. 18A, the cutaway that is provided at a positionnearest to the lock pin 401 z is the second camera cutaway 1401 e. Thethird camera cutaway 1401 f and first camera cutaway 1401 d are thenconsecutively provided in order from the second camera cutaway 1401 e ina clockwise direction.

As illustrated in FIG. 18C, a fitting member 1401 x that restrictsmovement of the camera accessory in a direction parallel to the opticalaxis when the camera accessory is mounted, is provided to the cameramount 1401 side. In the present embodiment, the diameter of the fittingmember 1401 x in a direction orthogonal to the optical axis at thecamera mount 1401 side is the mount diameter.

The way of bayonet coupling of the first conversion adapter 40 andsecond lens 50 is the generally the same as the way of bayonet couplingof the camera body 10 and first lens 100 described above, so descriptionwill be omitted.

Note that the end portions of the camera claw portions 1401 a, 1401 b,and 1401 c, in the circumferential direction, will be referred to asfirst end portion 1401 a 1, second end portion 1401 a 2, third endportion 1401 b 1, fourth end portion 1401 b 2, fifth end portion 1401 c1, and end portion 1401 c 2, for the sake of description. The endportions are denoted with part numerals in order from the first cameraclaw portion 1401 a in the clockwise direction, when viewing the cameramount 1401 from the rear face side, as described above.

As illustrated in FIG. 18A, the angles that the camera claw portions andcamera cutaways occupy in the circumferential direction of the cameramount 1401 (angle ranges) in the first conversion adapter 40 accordingto the present embodiment are stipulated as follows. For the firstcamera claw portion 1401 a, the angle θA1=56°, for the second cameraclaw portion 1401 b, the angle θA2=62°, and for the third camera clawportion 1401 c, the angle θA3=62°. Also, for the first camera cutaway1401 d, the angle is 57°, for the second camera cutaway 1401 e, theangle is 66°, and for the third camera cutaway 1401 f, the angle is 57°.That is to say the camera mount 1401 has different angles for the cameraclaw portions with respect to the above-described camera mount 201 ofthe camera body 10, but the angles of the camera cutaways are the same.

Also, when viewing the camera claw portions from the rear face side ofthe first conversion adapter 40, the angles where the camera clawportions are disposed on the circumferential direction of the cameramount 1401 with the position of the lock pin 402 (referred to asreference position) as a reference are stipulated as follows. The firstcamera claw portion 1401 a is disposed between 159° to 215° with thereference position as a start point. The second camera claw portion 1401b is disposed between 272° to 334° with the reference position as astart point. The third camera claw portion 1401 c is disposed between40° to 102° with the reference position as a start point.

Next, FIGS. 19A and 19B are diagrams exemplarily describing angles ofdisposing the bayonet claw portions on the lens mount 1101 provided tothe other end of the first conversion adapter 40. FIG. 19A is a diagramillustrating angle ranges that camera claw portions and camera cutawaysoccupy in the circumferential direction of the camera mount 1401 withthe lock pin groove 1102 as a reference, as viewed from the rear faceside. FIG. 19B is a diagram illustrating angle ranges that multiple lenscutaways 1101 a through 1101 c occupy in the circumferential directionof the lens mount 1101, as viewed from the rear face side. In FIG. 19A,1101 y is a circumferential-direction positioning pin 1101 y thatprevents the first conversion adapter 40 from rotating excessively fromthe desired position when the first conversion adapter 40 is mounted onthe camera body 10. By having the positioning pin 1101 y come in contactwith the fourth end 208 b 2, the first conversion adapter 40 is stoppedfrom rotating past the desired position described above. The first lens(the interchangeable lens assembly described in FIG. 2) 100 has acircumferential-direction positioning pin same as thecircumferential-direction positioning pin 1101 y.

The angles (angle ranges) that the lens cutaways occupy in thecircumferential direction of the lens mount 1101 are, represented by θA4as the angle of the first lens-side cutaway 1108 a and θA5 as the angleof the second lens-side cutaway 1108 b, as illustrated in FIG. 19B. Notethat the angle so disposing the claw portions and cutaways on the lensmount 1101 of the first conversion adapter 40 is the same as the lensmount 101 of the first lens 100 described above, and accordinglydescription will be omitted.

The angles of the claw portions and cutaways in the circumferentialdirection, on the lens mount 1101 and camera mount 1401 provided to thefirst conversion adapter 40, will be compared. For example, at the lensmount 1101 side, the angle θA5 of the second lens-side cutaway 1108 bhaving the smallest angle is 44°, whereas, at the camera mount 1401side, the angle θA1 of first camera claw portion 1401 a having thesmallest angle is 56°. That is to say, the claw portion having thesmallest angle at the camera mount 1401 side is larger than the cutawayhaving the smallest angle at the lens mount 1101 side (θA5<θA1). In thiscase, of the cutaways on the lens mount 1101 side and the claw portionson the camera mount 1401 side, at least one or more lens cutaway andcamera claw portions will interfere with each other. Accordingly, evenif an attempt is made to mount the interchangeable lens assembly to thecamera body so that the optical axis at the camera mount 1401 side andlens mount 1101 side are generally parallel, the claw portions andcutaways interfere, so the interchangeable lens assembly cannot bemounted to the camera body.

However, if only one claw portion and cutaway are interfering, there maybe cases where claw portions of the camera mount side can be insertedinto cutaways of the lens mount side. FIGS. 20A and 20B are diagramsexemplarily describing a mounting method of a predetermined imagingapparatus 1000 and a predetermined interchangeable lens assembly 2000having claw portions and cutaways that interfere with each other. FIG.20A is a diagram exemplarily describing a frontal view of partwaythrough mounting a predetermined interchangeable lens assembly to apredetermined imaging apparatus that have claw portions and cutawaysthat interfere with each other. FIG. 20B is a cross-sectional view takenalong cross-section XXB-XXB in FIG. 20A.

For example, in a state where the optical axis of the lens mount side isobliquely inclined as to the optical axis of the camera mount side, oneend of a camera claw portion is inserted into a lens cutaway, and fromthis state, the lens mount and camera mount are rotated relatively toeach other, as illustrated in FIGS. 20A and 20B. In this case, even ifthe camera claw portions and lens cutaways originally interfere witheach other, this interference with each other is resolved during therelative rotation of the lens mount and camera mount, and transition canbe made to a state where the camera claw portion is inserted into thislens cutaway. In this case, if there are no other camera claw portionsand lens cutaways interfering, the interchangeable lens assembly can bemounted to the camera body.

Accordingly, the claw portions and cutaways on the lens mount 1101 sideand camera mount 1401 side are disposed such that the angle of apredetermined lens cutaway adjacent to a reference lens claw portion issmaller than the angle of two camera claw portions adjacent to areference camera cutaway. Specifically, in the present embodiment, theangles θA4 and θA5 of the first lens-side cutaway 1108 a and secondlens-side cutaway 1108 b adjacent to the first lens-side claw portion1107 a are smaller than the angles θA1 and θA2 of the first camera clawportion 1401 a and second camera claw portion 1401 b adjacent to thefirst camera cutaway 1401 d. That is to say, θA4 (52°) is smaller thanθA1 (56°), and θA5 (44°) is smaller than θA2 (62°) (θA4<θA1, θA5<θA2).Accordingly, even if an attempt is made to insert the first lens-sideclaw portion 1107 a into the first camera cutaway 1401 d, the secondlens-side claw portion 1107 b interferes with the second camera clawportion 1401 b in a sure manner, as well does the third lens-side clawportion 1107 c with the first camera claw portion 1401 a, as illustratedin FIGS. 21A and 21B.

FIGS. 21A and 21B are diagrams exemplarily describing the way in whichclaw portions interfere with each other when attempting to mount thelens mount 101 side to the camera mount 1401 side according to theembodiment of the present invention. FIG. 21A illustrates the way inwhich the third lens-side claw portion 1107 c and the first camera clawportion 1401 a interfere, and FIG. 21B illustrates the way in which thesecond lens-side claw portion 1107 b and the second camera claw portion1401 b interfere.

As described above, incompatible interchangeable lens assemblies andimaging apparatuses, and the mount portions of conversion adapters areconfigured so that two claw portions of each other out of the clawportions that an incompatible interchangeable lens assembly and imagingapparatus have interfere with each other in the present embodiment.According to this configuration, the risk of an incompatibleinterchangeable lens assembly being erroneously mounted to an imagingapparatus, or an incompatible interchangeable lens assembly and imagingapparatus being erroneously mounted to mount units provided to both endsof a conversion adapter, can be reduced.

However, even in a case where the above conditions are satisfied, theremay be cases where, when attempting to insert three claw portions intoincompatible cutaways, for example, two claw portions are inserted intocutaways depending on the angles of the claw portions and cutaways.Accordingly, the present embodiment further takes a configuration wherethe angles of at least two adjacent lens cutaways are smaller than theangles of all camera claw portions. Specifically, in the presentembodiment, the angles θA4 and θA5 of the first lens-side cutaway 1108 aand second lens-side cutaway 1108 b in the circumferential direction aresmaller than the angles θA1 through θA3 of the first through thirdcamera claw portions 1401 a through 1401 c in the circumferentialdirection. That is to say, the relation between the claw portions andcutaways at the lens mount 1101 side and the camera mount 1401 sideaccording to the present embodiment satisfy θA4<θA1, θA4<θA2, θA4<θA3,θA5<θA1, θA5<θA2, and θA5<θA3.

FIGS. 22A through 22D is a diagram exemplarily describing a case ofattempting to insert incompatible claw portions into cutaways at thelens mount 1101 side and camera mount 1401 side according to theembodiment of the present invention. FIG. 22A illustrates the way inwhich the third lens-side claw portion 1107 c and third camera clawportion 1401 c interfere in a case of attempting to insert the firstlens-side claw portion 1107 a into the third camera cutaway 1401 f. FIG.22B illustrates the way in which second lens-side claw portion 1107 band first camera claw portion 1401 a interfere in a case of attemptingto insert the first lens-side claw portion 1107 a into the third cameracutaway 1401 f. FIG. 22C illustrates the way in which the thirdlens-side claw portion 1107 c and second camera claw portion 1401 binterfere in a case of attempting to insert the first lens-side clawportion 1107 a into the second camera cutaway 1401 e. FIG. 22Dillustrates the way in which the second lens-side claw portion 1107 band third camera claw portion 1401 c interfere in a case of attemptingto insert the first lens-side claw portion 1107 a into the second cameracutaway 1401 e.

As illustrated in FIGS. 22A through 22D, the lens claw portions andcamera claw portions interfere in at least two places in the presentembodiment, regardless of the relative rotational angle of the lensmount 1101 and camera mount 1401. According to this configuration,erroneous mounting of an interchangeable lens assembly and conversionadapter having the lens mount 101(1101) to an imaging apparatus andconversion adapter having the camera mount 401(1401) can be preventedeven more effectively.

Next, the angles (phases) at which bayonet claw portions are disposed onthe circumferential direction of the camera mount and lens mount of thesecond conversion adapter 70 will be described with reference to FIGS.22A through 27.

The second conversion adapter 70 is a mount adapter used for mountingthe first lens 100 that has a short flange focal distance to the camerabody 60 that has a long flange focal distance. The lens mount 1501 isprovided at one end (third end) side of the second conversion adapter70, and the camera mount 1201 is provided at the other end (fourth end).Note that the camera mount 1201 of the second conversion adapter 70 hasthe same configuration as the camera mount 201 of the camera body 10that is the first imaging apparatus described above. Also, the lensmount 1501 of the second conversion adapter 70 has the sameconfiguration as the lens mount 501 of the second lens 50 describedabove.

Accordingly, it is preferable for the second conversion adapter 70 to beconfigured such that the camera body 10 that has a short flange focaldistance cannot be directly mounted to the lens mount 1501, and thesecond lens 50 that has a long flange focal distance cannot be directlymounted to the camera mount 201. This configuration can be realized bysatisfying the positional relation of claw portions and cutaways so thatthe lens mount 1501 provided to one end (third end) of the secondconversion adapter 70 and the camera mount 1201 provided to the otherend (fourth end) cannot each be directly mounted.

FIGS. 23A and 23B are diagrams exemplarily describing angles ofdisposing bayonet claw portions in the camera mount 1201 provided on oneend of the second conversion adapter 70. FIG. 23A is a diagramillustrating angle ranges that camera claw portions and camera cutawaysoccupy in the circumferential direction of the camera mount 1201 withthe lock pin 1203 as a reference, as viewed from the rear face side.FIG. 23B is a diagram illustrating angle ranges that, regarding multiplecamera claw portions 1201 a through 1201 c, the claw portions occupy inthe circumferential direction of the camera mount 1201, as viewed fromthe rear face side. Note that the angles of disposing the claw portionsand cutaways on the camera mount 1201 of the second conversion adapter70 are the same as the camera mount 201 of the camera body 10 describedearlier, so description will be omitted.

As illustrated in FIG. 23B, the angle from the sixth end 1208 c 2 of thethird camera-side claw portion 1208 c to the third end 1208 b 1 of thesecond camera-side claw portion 1208 b, in the circumferential directionof the camera mount 1201 including the first camera-side claw portion1208 a, is θA6 (162°). The angle from the second end 1201 a 2 of thefirst camera-side claw portion 1208 a to the fifth end 1208 c 1 of thethird camera-side claw portion 1208 c, in the circumferential directionof the camera mount 1201 including the second camera-side claw portion1208 b, is θA7 (163°). The angle from the fourth end 1208 b 2 of thesecond camera-side claw portion 1208 b to the first end 1208 a 1 of thefirst camera-side claw portion 1208 a, in the circumferential directionof the camera mount 1201 including the third camera-side claw portion1208 c, is θA8 (215°).

Next, FIGS. 24A through 24C are diagrams exemplarily describing angle sodisposing bayonet claw portions in a lens mount 1501 provided on theother end of the second conversion adapter 70. FIG. 24A is a diagramillustrating angle ranges that lens claw portions and lens cutawaysoccupy in the circumferential direction of the lens mount 1501 with thelock pin 1501 z as a reference, as viewed from the rear face side. FIG.24B is a diagram illustrating angle ranges where cutaways are providedregarding the multiple lens cutaways 1501 a through 1501 c in thecircumferential direction of the lens mount 1501, as viewed from therear face side. FIG. 24C is a cross-sectional diagram taken alongcross-section XXIVC-XXIVC in FIG. 24B.

A first lens claw portion 1501 d, second lens claw portion 1501 e, andthird lens claw portion 1501 f, are provided in order, to the cameramount 1501 in the circumferential direction (inner radial direction).Note that in a case of viewing the lens mount 1501 from the rear faceside as illustrated in FIG. 24A, the lens claw portion that is providedat a position farthest from the lock groove 1501 z is the first lensclaw portion 1501 d. The second lens claw portion 501 e and third lensclaw portion 1501 f are then consecutively provided in order from thefirst lens claw portion 1501 d in a clockwise direction.

Also, cutaways which are a first lens cutaway 1501 a, second lenscutaway 1501 b, and third lens cutaway 1501 c are provided in order, tothe lens mount 1501 in the circumferential direction (inner radialdirection). Note that in a case of viewing the lens mount 1501 from therear face side as illustrated in FIG. 24A, the cutaway that is providedat a position nearest to the lock groove 1501 z is the third lenscutaway 1501 c. The first lens cutaway 1501 a and second lens cutaway1501 b are then consecutively provided in order from the third lenscutaway 1501 c in a clockwise direction.

Note that the end portions of the lens claw portions 1501 d, 1501 e, and1501 f, in the circumferential direction, will be referred to as firstend portion 1501 d 1, second end portion 1501 d 2, third end portion1501 e 1, fourth end portion 1501 e 2, fifth end portion 1501 f 1, andsixth end portion 1501 f 2, for the sake of description. The endportions are denoted with part numerals in order from the first lensclaw portion 1501 d in the clockwise direction, when viewing the lensmount 1501 from the rear face side, as described above.

As illustrated in FIG. 24A, the angles that the lens claw portions andlens cutaways occupy in the circumferential direction of the lens mount1501 (angle ranges) are stipulated as follows. The angle of the firstlens claw portion 1501 d is 53°, the angle of the second lens clawportion 1501 e is 62°, and the angle of the third lens claw portion 1501f is 53°. That is to say, the angles of the lens claw portions on thelens mount 1501 side are the same as the angles of the lens clawportions on the lens mount 1101 side described earlier.

On the other hand, the angles of the lens cutaways at the lens mount1501 side differ from the angles of the lens cutaways at the lens mount1101 side described above. Specifically, the angle of the first lenscutaway 1501 a is 60°, the angle of the second lens cutaway 1501 b is66°, and the angle of the third lens cutaway 1501 c is 66°.

Also, when viewing the lens claw portions from the rear face side of thecamera body 10, the angles in the clockwise direction where the lensclaw portions are disposed on the circumferential direction of the lensmount 1501 with the position of the lock groove 1501 z (referred to asreference position) as a reference are stipulated as follows. The firstlens claw portion 1501 d is disposed between 157° to 210° with thereference position as a start point. The second lens claw portion 1501 eis disposed between 276° to 338° with the reference position as a startpoint. The third lens claw portion 1501 f is disposed between 44° to 97°with the reference position as a start point.

As illustrated in FIG. 24C, a fitting member 1501 x that restrictsmovement of the imaging apparatus in a direction parallel to the opticalaxis when mounted to the imaging apparatus is provided to the lens mount1501 side. In the present embodiment, the diameter of the fitting member1501 x in a direction orthogonal to the optical axis at the camera mount1501 side is the mount diameter. The mount diameters of the cameramounts and lens mounts described above are generally the same length.

As illustrated in FIG. 24B, the angle from the fifth end 1501 f 1 of thethird lens claw portion 1501 f to the second end 1501 d 2 of the secondlens claw portion 1501 d, in the circumferential direction of the lensmount 501 including the first lens cutaway 1501 a, is θA9 (166°). Theangle from the first end 1501 d 1 of the first lens claw portion 1501 dto the fourth end 1501 e 2 of the second lens claw portion 501 e, in thecircumferential direction of the lens mount 1501 including the secondlens cutaway 1501 b, is θA10 (181°). The angle from the third end 1501 e1 of the second lens claw portion 1501 e to the sixth end 1501 f 2 ofthe third lens claw portion 1501 f, in the circumferential direction ofthe lens mount 1501 including the third lens cutaway 1501 c, is θA11(181°).

The angles of the claw portions and cutaways in the circumferentialdirection will be compared between the camera mount 1201 and lens mount1501 provided to the second conversion adapter 70. For example, theangle (92°) of the third camera claw portion at the camera mount 1201side is larger than the angles (66°) of the second and third lenscutaways 1501 b and 1501 c that are the largest angle of the lenscutaways at the lens mount 1501 side. That is to say, the angle of atleast one camera claw portion at the camera mount 1201 side is largerthan the angle of the lens cutaway having the largest angle at the lensmount 1501 side.

In this case, of the claw portions at the camera mount 1201 side andcutaways at the lens mount 1501 side, at least one or more camera clawportion and lens cutaway interfere with each other. Accordingly, even ifan attempt is made to mount the interchangeable lens assembly to thecamera body so that the optical axis at the camera mount 1201 side andlens mount 1501 side are generally parallel to each other, the clawportions and cutaways interfere, so the interchangeable lens assemblycannot be mounted to the camera body.

However, if only one claw portion and cutaway are interfering, there maybe cases where claw portions of the camera mount side can be insertedinto cutaways of the lens mount side, in the same way as the descriptionof the first conversion adapter made above. For example, there are caseswhere, in a state where the optical axis of the lens mount side isobliquely inclined as to the optical axis of the camera mount side, oneend of a camera claw portion is inserted into a lens cutaway, and thelens mount and camera mount are rotated relative to each other, and theinterchangeable lens assembly can be mounted to the camera body.

Accordingly, in the present embodiment, the claw portions and cutawaysat the camera mount 1201 side and the lens mount 1501 side are disposedso as to satisfy θA6<θA9 and θA7<θA10 in the circumferential direction.FIGS. 25A and 25B are diagrams exemplarily describing the way in whichclaw portions interfere with each other, when attempting to mount areference claw portion at the lens mount 1501 side to a referencecutaway at the camera mount 1201 side according to the embodiment of thepresent invention. FIG. 25A illustrates the way in which the third lensclaw portion 1501 f and the third camera-side claw portion 1208 cinterfere, and FIG. 25B illustrates the way in which the second lensclaw portion 1501 e and the third camera-side claw portion 1208 cinterfere.

As illustrated in FIGS. 25A and 25B, in a case where the reference firstlens claw portion 501 d is attempted to be inserted into the referencecamera cutaway 1201 d, for example, the third camera-side claw portion1208 c interferes with the second and third lens claw portions 1501 eand 1501 f.

That is to say, as viewed from the rear face side, the total sum of theangles of one reference lens claw portion, another lens claw portionadjacent thereto in the clockwise direction, and a lens cutaway situatedbetween these lens claw portions, is taken as a first angle. Also, asviewed from the rear face side, the total sum of the angles of onereference camera cutaway, another camera cutaway adjacent thereto in theclockwise direction, and a camera claw portion situated therebetween, istaken as a second angle. Also, as viewed from the rear face side, thetotal sum of the angles of one reference lens claw portion, another lensclaw portion adjacent thereto in the counterclockwise direction, and alens cutaway situated between these lens claw portions, is taken as afirst angle. Also, as viewed from the rear face side, the total sum ofthe angles of one reference camera cutaway, another camera cutawayadjacent thereto in the counterclockwise direction, and a camera clawportion situated therebetween, is taken as a fourth angle. According tothe present embodiment, it is sufficient to layout the claw portions andcutaways at the camera mount 1201 side and lens mount 1501 side suchthat the first angle described above is larger than the second angle,and the third angle is larger than the fourth angle.

According to this configuration, at least two lens claw portions and onecamera claw portion interfere with each other. Thus, the risk of anincompatible interchangeable lens assembly being erroneously mounted toan imaging apparatus, or an incompatible interchangeable lens assemblyand imaging apparatus being erroneously mounted to mount units providedto both ends of a conversion adapter, can be reduced.

However, even in a case where the above conditions are satisfied, theremay be cases where, when attempting to insert three claw portions intoincompatible cutaways, for example, two claw portions are inserted intocutaways depending on the angles of the claw portions and cutaways.Accordingly, the claw portions and cutaways at the camera mount 1201side and lens mount 1501 side are disposed in the circumferentialdirection so as to satisfy θA6<θA9, θA6<θA10, θA6<θA11, θA7<θA9,θA7<θA10, and θA7<θA11. That is to say, as viewed from the rear faceside, the total sum of the angles of two claw portions other than thereference claw portion described above, and a lens cutaway situatedtherebetween, is taken as a fifth angle. According to the presentembodiment, it is sufficient to layout the claw portions and cutaways atthe camera mount 1201 side and lens mount 1501 side such that the secondangle and fourth angle described above are smaller than any of the firstangle, third angle, and fifth angle.

FIGS. 26A through 25D are diagrams exemplarily describing the way inwhich claw portions interfere with each other, when attempting to mounta claw portion other than the reference claw portion at the lens mount1501 side to a reference cutaway at the camera mount 1201 side accordingto the embodiment of the present invention. FIG. 26A illustrates the wayin which the first lens claw portion 1501 d and the third camera-sideclaw portion 1208 c interfere in a case of attempting to insert thesecond lens claw portion 1501 e into the second camera-side cutaway 1209b. FIG. 26B illustrates the way in which the third lens claw portion1501 c and the third camera-side claw portion 1208 c interfere in a caseof attempting to insert the second lens claw portion 1501 e into thesecond camera-side cutaway 1209 b. FIG. 26C illustrates the way in whichthe second lens claw portion 1501 e and the third camera-side clawportion 1208 c interfere in a case of attempting to insert the thirdlens claw portion 1501 f into the second camera-side cutaway 1209 b.FIG. 26D illustrates the way in which the first lens claw portion 1501 dand the third camera-side claw portion 1208 c interfere in a case ofattempting to insert the third lens claw portion 1501 f into the secondcamera-side cutaway 1209 b.

As illustrated in FIGS. 26A through 26D, at least two lens claw portionsand one camera claw portion interfere, regardless of the relativerotation angle of the lens mount 501 and camera mount 1201 according tothe present embodiment. According to this configuration, erroneousmounting of an interchangeable lens assembly and conversion adapterhaving the lens mount 501 (1501) to an imaging apparatus and conversionadapter having the camera mount 201 (1201) can be prevented even moreeffectively.

FIG. 27 is a diagram exemplarily describing a state in which clawportions provided to the camera mount 1401 side and lens mount 1501 sideaccording to the embodiment of the present invention are engaged. Thefirst lens claw portion 1501 d can be inserted into the first cameracutaway 1401 d, as illustrated in FIG. 27. Also, the second lens clawportion 1501 e can be inserted into the second camera cutaway 1401 e.Further, the third lens claw portion 1501 f can be inserted into thethird camera cutaway 1401 f. That is to say, the camera mount 1401 sideand the lens mount 1501 side are a combination compatible with beingdirectly mounted to each other. Note that the camera mount 201 side andthe lens mount 101 side are a combination compatible to being directlymounted to each other, as illustrated in FIG. 15A.

As described above, the camera mount 1401 corresponding to an imagingapparatus that has a long flange focal distance (e.g., the camera body60), and the lens mount 501 corresponding to an interchangeable lensassembly that has a long flange focal distance (e.g., the second lens50) can be directly mounted to each other. However, the camera mount 201corresponding to an imaging apparatus having a short flange focaldistance (e.g., the camera body 10) and the lens mount 501 correspondingto an interchangeable lens assembly that has a long flange focaldistance (e.g., the second lens 50) cannot be directly mounted to eachother. Also, the camera mount 201 corresponding to an imaging apparatusthat has a short flange focal distance (e.g., the camera body 10) andthe lens mount 101 corresponding to an interchangeable lens assemblythat has a short flange focal distance (e.g., the first lens 100) can bedirectly mounted to each other. However, the camera mount 1401corresponding to an imaging apparatus that has a long flange focaldistance (e.g., the camera body 60) and the lens mount 101 correspondingto an interchangeable lens assembly that has a short flange focaldistance (e.g., the first lens 100) cannot be directly mounted to eachother.

Accordingly, an imaging apparatus and camera accessory employing theconfiguration of the above-described embodiment can prevent erroneousmounting of an imaging apparatus and camera accessory that havegenerally the same mount diameter but are not mutually compatible.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments.

This application claims the benefit of Japanese Patent Application No.2017-108265 filed May 31, 2017, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An accessory configured to be detachablymountable to an image pickup apparatus that includes a first mountportion and a pin, the first mount portion including a plurality offirst bayonet claw portions, the accessory comprising: a second mountportion that includes a plurality of second bayonet claw portionsconfigured to enable engagement with the plurality of first bayonet clawportions, and a concave portion in which the pin is inserted when theaccessory is mounted to the image pickup apparatus, wherein when viewedin a central axis direction of the second mount portion, a concaveportion side is a side on which the concave portion is provided withrespect to a boundary line, the boundary line being a line that isorthogonal to a line passing through a center of the concave portion anda central axis of the second mount portion and that passes through thecentral axis of the second mount portion, among the plurality of secondbayonet claw portions, two second bayonet claw portions that have atleast a portion disposed on the concave portion side are denoted as afirst concave portion side bayonet claw portion and a second concaveportion side bayonet claw portion, the plurality of second bayonet clawportions include the first concave portion side bayonet claw portion,the second concave portion side bayonet claw portion, and an oppositeside bayonet claw portion in which both ends thereof are provided onopposite side of the concave portion side with respect to the boundaryline, whereinθ10+θ20+θ30+θL=360°, and75°≤≤10≤105°,75°≤θ20≤105°,75°≤θ30≤105°, and 75°≤θL≤105° are satisfied,where, among internal angles of a quadrangle formed by connecting acenter of the opposite side bayonet claw portion, a center of the secondconcave portion side bayonet claw portion, a center of the first concaveportion side bayonet claw portion, and the center of the concaveportion, θ10 is an angle of a first internal angle in which a vertexthereof is the center of the opposite side bayonet claw portion, θ20 isan angle of a second internal angle in which a vertex thereof is thecenter of the second concave portion side bayonet claw portion, θ30 isan angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.
 2. The accessory according to claim 1,wherein at least one among θ10, θ20, θ30, and θL is in a range of 85 to95, inclusive.
 3. The accessory according to claim 1, wherein85°≤θL≤95° is satisfied.
 4. The accessory according to claim 1, wherein0.75≤θ30/θ20≤1.25 is satisfied.
 5. The accessory according to claim 1,whereinθ1>θ2, and 1.00<θ1/θ2≤1.40 are satisfied, where θ1 is an angle formedbetween a line that passes through an end of the first concave portionside bayonet claw portion that is closer to the concave portion, and thecentral axis of the second mount portion, and a line that passes throughthe center of the concave portion and the central axis of the secondmount portion, and θ2 is an angle formed between a line that passesthrough an end of the second concave portion side bayonet claw portionthat is closer to the concave portion, and the central axis of thesecond mount portion, and a line that passes through the center of theconcave portion and the central axis of the second mount portion.
 6. Theaccessory according to claim 5, wherein1.00<θ1/θ2≤1.35 is satisfied.
 7. The accessory according to claim 1,wherein when viewed in the central axis direction of the second mountportion, a line that passes through the center of the concave portionand the central axis of the second mount portion, and the opposite sidebayonet claw portion overlap each other.
 8. The accessory according toclaim 1, wherein0.6≤θ3/θ4≤0.9 is satisfied, where θ3 is an angle formed between a linethat passes through an end of the opposite side bayonet claw portionthat is on the side of the first concave portion side bayonet clawportion, and the central axis of the second mount portion, and a linethat passes through the center of the concave portion and the centralaxis of the second mount portion, and θ4 is an angle formed between aline passing through an end of the opposite side bayonet claw portionthat is on the side of the second concave portion side bayonet clawportion, and the central axis of the second mount portion, and a linethat passes through the center of the concave portion and the centralaxis of the second mount portion.
 9. The accessory according to claim 1,wherein90°<θ1+θ2<180° is satisfied, where θ1 is an angle formed between a linethat passes through an end of the first concave portion side bayonetclaw portion that is closer to the concave portion, and the central axisof the second mount portion, and a line that passes through the centerof the concave portion and the central axis of the second mount portion,and θ2 is an angle formed between a line that passes through an end ofthe second concave portion side bayonet claw portion that is closer tothe concave portion, and the central axis of the second mount portion,and a line that passes through the center of the concave portion and thecentral axis of the second mount portion.
 10. The accessory according toclaim 1, wherein40°<θ1<70°, and40°<θ2<70° are satisfied, where θ1 is an angle formed between a linethat passes an end of the first concave portion side bayonet clawportion that is closer to the concave portion, and the central axis ofthe second mount portion, and a line that passes the center of theconcave portion and the central axis of the second mount portion, and θ2is an angle formed between a line that passes an end of the secondconcave portion side bayonet claw portion that is closer to the concaveportion, and the central axis of the second mount portion, and a linethat passes the center of the concave portion and the central axis ofthe second mount portion.
 11. The accessory according to claim 1,wherein when viewed in the central axis direction of the second mountportion, the first concave portion side bayonet claw portion and thesecond concave portion side bayonet claw portion both overlap theboundary line.
 12. The accessory according to claim 1, wherein wherein afirst cutaway is a portion between the first concave portion sidebayonet claw portion and the opposite side bayonet claw portion, asecond cutaway is a portion between the opposite side bayonet clawportion and the second concave portion side bayonet claw portion, and athird cutaway is a portion between the second concave portion sidebayonet claw portion and the first concave portion side bayonet clawportion, a dimension of the third cutaway in a circumferential directionof the accessory is larger than dimensions of the first cutaway and thesecond cutaway in the circumferential direction of the accessory. 13.The accessory according to claim 1, wherein, among the plurality offirst bayonet claw portions, a third bayonet claw portion is a firstbayonet claw portion configured to enable engagement with the oppositeside bayonet claw portion, a fourth bayonet claw portion is a firstbayonet claw portion configured to enable engagement with the secondconcave portion side bayonet claw portion, and a fifth bayonet clawportion is a first bayonet claw portion configured to enable engagementwith the first concave portion side bayonet claw portion, and, when theaccessory mounted to the image pickup apparatus is viewed in the centralaxis direction of the second mount portion, a reference line is a linethat connects the central axis of the second mount portion and a centerof the pin to each other, θ5 is an angle formed between a line thatconnects a point that is, in a region where the first concave portionside bayonet claw portion and the fifth bayonet claw portion overlapeach other, nearest to the pin and the central axis of the second mountportion, and the reference line, θ6 is an angle formed between a linethat connects a point that is, in a region where the second concaveportion side bayonet claw portion and the fourth bayonet claw portionoverlap each other, nearest to the pin and the central axis of thesecond mount portion, and the reference line θ6, θ7 is a minimum valueof θ5, and θ8 is a minimum value of θ6,0.75≤θ7/θ8≤1.25 is satisfied.
 14. The accessory according to claim 1,wherein90°<θ7+θ8<180°,and90°<θ9+θ8<180° are satisfied, where among the plurality of first bayonetclaw portions, a third bayonet claw portion is a first bayonet clawportion configured to enable engagement with the opposite side bayonetclaw portion, a fourth bayonet claw portion is a first bayonet clawportion configured to enable engagement with the second concave portionside bayonet claw portion, and a fifth bayonet claw portion is a firstbayonet claw portion configured to enable engagement with the firstconcave portion side bayonet claw portion, and when the accessorymounted on the image pickup apparatus is viewed in the central axisdirection of the second mount portion, a reference line is a line thatconnects the central axis of the second mount portion and a center ofthe pin to each other, θ5 is an angle formed between a line thatconnects a point that is, in a region where the first concave portionside bayonet claw portion and the fifth bayonet claw portion overlapeach other, nearest to the pin and the central axis of the second mountportion, and the reference line, θ6 is an angle formed between a linethat connects a point that is, in a region where the second concaveportion side bayonet claw portion and the fourth bayonet claw portionoverlap each other, nearest to the pin and the central axis of thesecond mount portion, and the reference line θ6, θ7 is a minimum valueof θ5, and θ8 is a minimum value of θ6, a maximum value of θ5 is θ9. 15.The accessory according to claim 1, wherein, among the plurality offirst bayonet claw portions, a third bayonet claw portion is a firstbayonet claw portion configured to enable engagement with the oppositeside bayonet claw portion, a fourth bayonet claw portion is a firstbayonet claw portion configured to enable engagement with the secondconcave portion side bayonet claw portion, and a fifth bayonet clawportion is a first bayonet claw portion configured to enable engagementwith the first concave portion side bayonet claw portion, and when theaccessory mounted on the image pickup apparatus is viewed in the centralaxis direction of the second mount portion, among sides of a hexagonpassing through a first end and a second end of a region where the firstconcave portion side bayonet claw portion and the fifth bayonet clawportion overlap each other, a first end and a second end of a regionwhere the second concave portion side bayonet claw portion and thefourth bayonet claw portion overlap each other, and a first end and asecond end of a region where the opposite side bayonet claw portion andthe third bayonet claw portion overlap each other, the side nearest tothe pin is a longest side of the hexagon.
 16. The accessory according toclaim 1, wherein by having the accessory rotate relative to the imagepickup apparatus, the accessory can be transitioned from a first statein which the plurality of second bayonet claw portions are positionedbetween the plurality of first bayonet claw portions to a second statein which the plurality of second bayonet claw portions are engaged withthe plurality of first bayonet claw portion.
 17. The accessory accordingto claim 1, further comprising: a plurality of second terminalsconfigured to contact a plurality of first terminals included in theimage pickup apparatus, wherein the plurality of second terminals areprovided at positions that are different from positions of the pluralityof second bayonet claw portions.
 18. The accessory according to claim17, wherein the plurality of second terminals include a second terminalconfigured to determine whether the accessory is mounted on the imagepickup apparatus or not.
 19. The accessory according to claim 18,wherein the plurality of second terminals include a second terminalconfigured to distinguish a type of the accessory mounted to the imagepickup apparatus.
 20. The accessory according to claim 19, wherein theplurality of second terminals include a second terminal configured toconnect the image pickup apparatus and a communication control system ofthe accessory to the ground, and a second terminal configured to supplypower, used in an operation of the communication control system, fromthe image pickup apparatus to the accessory.
 21. The accessory accordingto claim 20, wherein the plurality of second terminals include a secondterminal configured to connect the image pickup apparatus and amechanical drive system of the accessory to the ground, and a secondterminal configured to supply power, used in the operation of themechanical drive system, from the image pickup apparatus to theaccessory.
 22. The accessory according to claim 21, wherein theplurality of second terminals include a first communication unitconfigured to perform a first communication, wherein the firstcommunication unit includes a second terminal configured to communicateclock signal that is output from the image pickup apparatus to theaccessory, a second terminal configured to enable two-way communicationbetween the image pickup apparatus and the accessory, and a secondterminal configured to communicate a data that is output from theaccessory to the image pickup apparatus.
 23. The accessory according toclaim 22, wherein the plurality of second terminals include a secondcommunication unit configured to perform a second communicationindependent of the first communication, and wherein the secondcommunication unit includes a second terminal configured to communicatea data that is output from the accessory to the image pickup apparatus.24. The accessory according to claim 23, wherein the plurality of secondterminals include a third communication unit configured to perform athird communication independent of the first communication and thesecond communication, wherein the third communication unit includes asecond terminal configured to enable two-way communication between theimage pickup apparatus and the accessory, and a second terminalconfigured to communicate a communication request signal between theimage pickup apparatus and the accessory.
 25. The accessory according toclaim 22, wherein the accessory is a lens apparatus including a lens,and wherein the central axis of the second mount portion is an opticalaxis of the lens.
 26. The accessory according to claim 1, wherein theaccessory is an adapter configured to be detachably mountable betweenthe lens apparatus and the image pickup apparatus, and wherein thecentral axis of the second mount portion is a central axis of an openingincluded in the second mount portion.
 27. The accessory according toclaim 1, wherein when the accessory is in a normal position, the secondconcave portion side bayonet claw portion is positioned on a gravitydirection side with respect to the first concave portion side bayonetclaw portion.
 28. The accessory according to claim 1, wherein theconcave portion is provided at a cutaway between the first concaveportion side bayonet claw portion and the second concave portion sidebayonet claw portion.
 29. The accessory according to claim 9, whereinthe concave portion is provided at a cutaway between the first concaveportion side bayonet claw portion and the second concave portion sidebayonet claw portion.
 30. An image pickup apparatus comprising: a firstmount portion including a plurality of first bayonet claw portions; apin; and an image pickup element, wherein the image pickup apparatusconfigured such that an accessory is detachably mountable to the imagepickup apparatus, wherein the accessory comprises, a second mountportion that includes a plurality of second bayonet claw portionsconfigured to enable engagement with the plurality of first bayonet clawportions, and a concave portion in which the pin is inserted when theaccessory is mounted to the image pickup apparatus, when viewed in acentral axis direction of the second mount portion, a concave portionside is a side on which the concave portion is provided with respect toa boundary line, the boundary line being a line that is orthogonal to aline passing through a center of the concave portion and a central axisof the second mount portion and that passes through the central axis ofthe second mount portion, among the plurality of second bayonet clawportions, two second bayonet claw portions that have at least a portiondisposed on the concave portion side are denoted as a first concaveportion side bayonet claw portion and a second concave portion sidebayonet claw portion, the plurality of second bayonet claw portionsinclude the first concave portion side bayonet claw portion, the secondconcave portion side bayonet claw portion, and an opposite side bayonetclaw portion in which both ends thereof are provided on opposite side ofthe concave portion side with respect to the boundary line, whereinθ10+θ20+θ30+θL=360°, and75°≤θ10≤105°,75°≤θ20≤105°,75°≤θ30≤105°, and 75°≤θL≤105° are satisfied,where, among internal angles of a quadrangle formed by connecting acenter of the opposite side bayonet claw portion, a center of the secondconcave portion side bayonet claw portion, a center of the first concaveportion side bayonet claw portion, and the center of the concaveportion, θ10 is an angle of a first internal angle in which a vertexthereof is the center of the opposite side bayonet claw portion, θ20 isan angle of a second internal angle in which a vertex thereof is thecenter of the second concave portion side bayonet claw portion, θ30 isan angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.
 31. A camera system comprising: an imagepickup apparatus including a first mount portion including a pluralityof first bayonet claw portions, a pin, and an image pickup element; andan accessory, wherein the accessory comprises, a second mount portionthat includes a plurality of second bayonet claw portions configured toenable engagement with the plurality of first bayonet claw portions, anda concave portion in which the pin is inserted when the accessory ismounted to the image pickup apparatus, when viewed in a central axisdirection of the second mount portion, a concave portion side is a sideon which the concave portion is provided with respect to a boundaryline, the boundary line being a line that is orthogonal to a linepassing through a center of the concave portion and a central axis ofthe second mount portion and that passes through the central axis of thesecond mount portion, among the plurality of second bayonet clawportions, two second bayonet claw portions that have at least a portiondisposed on the concave portion side are denoted as a first concaveportion side bayonet claw portion and a second concave portion sidebayonet claw portion, the plurality of second bayonet claw portionsinclude the first concave portion side bayonet claw portion, the secondconcave portion side bayonet claw portion, and an opposite side bayonetclaw portion in which both ends thereof are provided on opposite side ofthe concave portion side with respect to the boundary line, whereinθ10+θ20+θ30+θL=360°, and75°≤θ10≤105°,75°≤θ20≤105°,75°≤θ30≤105°, and 75°≤θL≤105° are satisfied,where, among internal angles of a quadrangle formed by connecting acenter of the opposite side bayonet claw portion, a center of the secondconcave portion side bayonet claw portion, a center of the first concaveportion side bayonet claw portion, and the center of the concaveportion, θ10 is an angle of a first internal angle in which a vertexthereof is the center of the opposite side bayonet claw portion, θ20 isan angle of a second internal angle in which a vertex thereof is thecenter of the second concave portion side bayonet claw portion, θ30 isan angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.
 32. An accessory configured to bedetachably mountable to an image pickup apparatus that includes a firstmount portion and a pin, the first mount portion including a pluralityof first bayonet claw portions, the accessory comprising: a second mountportion that includes a plurality of second bayonet claw portionsconfigured to enable engagement with the plurality of first bayonet clawportions, and a concave portion in which the pin is inserted when theaccessory is mounted to the image pickup apparatus, wherein when viewedin a central axis direction of the second mount portion, a concaveportion side is a side on which the concave portion is provided withrespect to a boundary line, the boundary line being a line that isorthogonal to a line passing through a center of the concave portion anda central axis of the second mount portion and that passes through thecentral axis of the second mount portion, among the plurality of secondbayonet claw portions, two second bayonet claw portions that have atleast a portion disposed on the concave portion side are denoted as afirst concave portion side bayonet claw portion and a second concaveportion side bayonet claw portion, the plurality of second bayonet clawportions include the first concave portion side bayonet claw portion,the second concave portion side bayonet claw portion, and an oppositeside bayonet claw portion in which both ends thereof are provided onopposite side of the concave portion side with respect to the boundaryline, whereinθ10+θ20+θ30+θL=360°, and60°≤θ10≤100°,60°≤θ20≤100°,60°≤θ30≤100°, and 60°≤θL≤100° are satisfied,where, among internal angles of a quadrangle formed by connecting acenter of the opposite side bayonet claw portion, a center of the secondconcave portion side bayonet claw portion, a center of the first concaveportion side bayonet claw portion, and the center of the concaveportion, θ10 is an angle of a first internal angle in which a vertexthereof is the center of the opposite side bayonet claw portion, θ20 isan angle of a second internal angle in which a vertex thereof is thecenter of the second concave portion side bayonet claw portion, θ30 isan angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.
 33. An image pickup apparatus comprising:a first mount portion including a plurality of first bayonet clawportions; a pin; and an image pickup element, wherein the image pickupapparatus is configured such that an accessory is detachably mountableto the image pickup apparatus, wherein the accessory comprises, a secondmount portion that includes a plurality of second bayonet claw portionsconfigured to enable engagement with the plurality of first bayonet clawportions, and a concave portion in which the pin is inserted when theaccessory is mounted to the image pickup apparatus, when viewed in acentral axis direction of the second mount portion, a concave portionside is a side on which the concave portion is provided with respect toa boundary line, the boundary line being a line that is orthogonal to aline passing through a center of the concave portion and a central axisof the second mount portion and that passes through the central axis ofthe second mount portion, among the plurality of second bayonet clawportions, two second bayonet claw portions that have at least a portiondisposed on the concave portion side are denoted as a first concaveportion side bayonet claw portion and a second concave portion sidebayonet claw portion, the plurality of second bayonet claw portionsinclude the first concave portion side bayonet claw portion, the secondconcave portion side bayonet claw portion, and an opposite side bayonetclaw portion in which both ends thereof are provided on opposite side ofthe concave portion side with respect to the boundary line, whereinθ10+θ20+θ30+θL=360°, and60°≤θ10≤100°,60°≤θ20≤100°,60°≤θ30≤100°, and 60°≤θL≤100° are satisfied,where, among internal angles of a quadrangle formed by connecting acenter of the opposite side bayonet claw portion, a center of the secondconcave portion side bayonet claw portion, a center of the first concaveportion side bayonet claw portion, and the center of the concaveportion, θ10 is an angle of a first internal angle in which a vertexthereof is the center of the opposite side bayonet claw portion, θ20 isan angle of a second internal angle in which a vertex thereof is thecenter of the second concave portion side bayonet claw portion, θ30 isan angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.
 34. A camera system comprising: an imagepickup apparatus including a first mount portion including a pluralityof first bayonet claw portions, a pin, and an image pickup element; andan accessory, wherein the accessory comprises, a second mount portionthat includes a plurality of second bayonet claw portions configured toenable engagement with the plurality of first bayonet claw portions, anda concave portion in which the pin is inserted when the accessory ismounted to the image pickup apparatus, when viewed in a central axisdirection of the second mount portion, a concave portion side is a sideon which the concave portion is provided with respect to a boundaryline, the boundary line being a line that is orthogonal to a linepassing through a center of the concave portion and a central axis ofthe second mount portion and that passes through the central axis of thesecond mount portion, among the plurality of second bayonet clawportions, two second bayonet claw portions that have at least a portiondisposed on the concave portion side are denoted as a first concaveportion side bayonet claw portion and a second concave portion sidebayonet claw portion, the plurality of second bayonet claw portionsinclude the first concave portion side bayonet claw portion, the secondconcave portion side bayonet claw portion, and an opposite side bayonetclaw portion in which both ends thereof are provided on opposite side ofthe concave portion side with respect to the boundary line, whereinθ10+θ20+θ30+θL=360°, and60°≤θ10≤100°,60°≤θ20≤100°,60°≤θ30≤100°, and 60°≤θL≤100° are satisfied,where, among internal angles of a quadrangle formed by connecting acenter of the opposite side bayonet claw portion, a center of the secondconcave portion side bayonet claw portion, a center of the first concaveportion side bayonet claw portion, and the center of the concaveportion, θ10 is an angle of a first internal angle in which a vertexthereof is the center of the opposite side bayonet claw portion, θ20 isan angle of a second internal angle in which a vertex thereof is thecenter of the second concave portion side bayonet claw portion, θ30 isan angle of a third internal angle in which a vertex thereof is thecenter of the first concave portion side bayonet claw portion, and θL isan angle of a fourth internal angle in which a vertex thereof is thecenter of the concave portion.